Implement desktop capture API on OS X.

atom.gyp

@@ -245,6 +245,10 @@
         'vendor/node/deps/cares/include',
         # The `third_party/WebKit/Source/platform/weborigin/SchemeRegistry.h` is using `platform/PlatformExport.h`.
         '<(libchromiumcontent_src_dir)/third_party/WebKit/Source',
+        # The 'third_party/libyuv/include/libyuv/scale_argb.h' is using 'libyuv/basic_types.h'.
+        '<(libchromiumcontent_src_dir)/third_party/libyuv/include',
+        # The 'third_party/webrtc/modules/desktop_capture/desktop_frame.h' is using 'webrtc/base/scoped_ptr.h'.
+        '<(libchromiumcontent_src_dir)/third_party/',
       ],
       'direct_dependent_settings': {
         'include_dirs': [

atom/browser/api/atom_api_desktop_capturer.cc

@@ -0,0 +1,127 @@
+// Copyright (c) 2015 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/api/atom_api_desktop_capturer.h"
+
+#include "atom/common/api/atom_api_native_image.h"
+#include "atom/common/native_mate_converters/callback.h"
+#include "atom/common/node_includes.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/media/desktop_media_list.h"
+#include "native_mate/dictionary.h"
+#include "native_mate/handle.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_capture_options.h"
+#include "third_party/webrtc/modules/desktop_capture/screen_capturer.h"
+#include "third_party/webrtc/modules/desktop_capture/window_capturer.h"
+
+namespace mate {
+
+template<>
+struct Converter<DesktopMediaList::Source> {
+  static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
+                                   const DesktopMediaList::Source& source) {
+    mate::Dictionary dict(isolate, v8::Object::New(isolate));
+    content::DesktopMediaID id = source.id;
+    dict.Set("name", base::UTF16ToUTF8(source.name));
+    dict.Set("id", id.ToString());
+    dict.Set("thumbnail",
+        atom::api::NativeImage::Create(isolate, gfx::Image(source.thumbnail)));
+    return ConvertToV8(isolate, dict);
+  }
+};
+
+}  // namespace mate
+
+namespace atom {
+
+namespace api {
+
+namespace {
+// The wrapDesktopCapturer funtion which is implemented in JavaScript
+using WrapDesktopCapturerCallback = base::Callback<void(v8::Local<v8::Value>)>;
+WrapDesktopCapturerCallback g_wrap_desktop_capturer;
+
+const int kThumbnailWidth = 150;
+const int kThumbnailHeight = 150;
+}  // namespace
+
+DesktopCapturer::DesktopCapturer(bool show_screens, bool show_windows) {
+  scoped_ptr<webrtc::ScreenCapturer> screen_capturer(
+      show_screens ? webrtc::ScreenCapturer::Create() : nullptr);
+  scoped_ptr<webrtc::WindowCapturer> window_capturer(
+      show_windows ? webrtc::WindowCapturer::Create() : nullptr);
+  media_list_.reset(new NativeDesktopMediaList(screen_capturer.Pass(),
+      window_capturer.Pass()));
+  media_list_->SetThumbnailSize(gfx::Size(kThumbnailWidth, kThumbnailHeight));
+  media_list_->StartUpdating(this);
+}
+
+DesktopCapturer::~DesktopCapturer() {
+}
+
+const DesktopMediaList::Source& DesktopCapturer::GetSource(int index) {
+  return media_list_->GetSource(index);
+}
+
+void DesktopCapturer::OnSourceAdded(int index) {
+  Emit("source-added", index);
+}
+
+void DesktopCapturer::OnSourceRemoved(int index) {
+  Emit("source-removed", index);
+}
+
+void DesktopCapturer::OnSourceMoved(int old_index, int new_index) {
+  Emit("source-moved", old_index, new_index);
+}
+
+void DesktopCapturer::OnSourceNameChanged(int index) {
+  Emit("source-name-changed", index);
+}
+
+void DesktopCapturer::OnSourceThumbnailChanged(int index) {
+  Emit("source-thumbnail-changed", index);
+}
+
+mate::ObjectTemplateBuilder DesktopCapturer::GetObjectTemplateBuilder(
+      v8::Isolate* isolate) {
+  return mate::ObjectTemplateBuilder(isolate)
+      .SetMethod("getSource", &DesktopCapturer::GetSource);
+}
+
+void SetWrapDesktopCapturer(const WrapDesktopCapturerCallback& callback) {
+  g_wrap_desktop_capturer = callback;
+}
+
+void ClearWrapDesktopCapturer() {
+  g_wrap_desktop_capturer.Reset();
+}
+
+// static
+mate::Handle<DesktopCapturer> DesktopCapturer::Create(v8::Isolate* isolate,
+    bool show_screens, bool show_windows) {
+  auto handle = mate::CreateHandle(isolate,
+      new DesktopCapturer(show_screens, show_windows));
+  g_wrap_desktop_capturer.Run(handle.ToV8());
+  return handle;
+}
+
+}  // namespace api
+
+}  // namespace atom
+
+namespace {
+
+void Initialize(v8::Local<v8::Object> exports, v8::Local<v8::Value> unused,
+                v8::Local<v8::Context> context, void* priv) {
+  v8::Isolate* isolate = context->GetIsolate();
+  mate::Dictionary dict(isolate, exports);
+  dict.SetMethod("_setWrapDesktopCapturer", &atom::api::SetWrapDesktopCapturer);
+  dict.SetMethod("_clearWrapDesktopCapturer",
+                 &atom::api::ClearWrapDesktopCapturer);
+}
+
+}  // namespace
+
+NODE_MODULE_CONTEXT_AWARE_BUILTIN(atom_browser_desktop_capturer, Initialize);

atom/browser/api/atom_api_desktop_capturer.h

@@ -0,0 +1,51 @@
+// Copyright (c) 2015 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_BROWSER_API_ATOM_API_DESKTOP_CAPTURER_
+#define ATOM_BROWSER_API_ATOM_API_DESKTOP_CAPTURER_
+
+#include "base/memory/scoped_ptr.h"
+#include "atom/browser/api/event_emitter.h"
+#include "chrome/browser/media/desktop_media_list_observer.h"
+#include "chrome/browser/media/native_desktop_media_list.h"
+#include "native_mate/handle.h"
+
+namespace atom {
+
+namespace api {
+
+class DesktopCapturer: public mate::EventEmitter,
+                       public DesktopMediaListObserver {
+ public:
+  static mate::Handle<DesktopCapturer> Create(v8::Isolate* isolate,
+    bool show_screens, bool show_windows);
+
+  const DesktopMediaList::Source& GetSource(int index);
+
+ protected:
+  DesktopCapturer(bool show_screens, bool show_windows);
+  ~DesktopCapturer();
+
+  // DesktopMediaListObserver overrides.
+  void OnSourceAdded(int index) override;
+  void OnSourceRemoved(int index) override;
+  void OnSourceMoved(int old_index, int new_index) override;
+  void OnSourceNameChanged(int index) override;
+  void OnSourceThumbnailChanged(int index) override;
+
+ private:
+  // mate::Wrappable:
+  mate::ObjectTemplateBuilder GetObjectTemplateBuilder(
+      v8::Isolate* isolate) override;
+
+  scoped_ptr<DesktopMediaList> media_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(DesktopCapturer);
+};
+
+}  // namespace api
+
+}  // namespace atom
+
+#endif  // ATOM_BROWSER_API_ATOM_API_DESKTOP_CAPTURER_

atom/browser/api/atom_api_screen.cc

@@ -56,6 +56,21 @@ Screen::~Screen() {
   screen_->RemoveObserver(this);
 }
 
+mate::Handle<atom::api::DesktopCapturer> Screen::GetDesktopCapturer(
+    const std::vector<std::string>& sources) {
+  bool show_screens = false;
+  bool show_windows = false;
+  for (const auto& source_type : sources) {
+    if (source_type == "screen") {
+      show_screens = true;
+    } else if (source_type == "window") {
+      show_windows = true;
+    }
+  }
+
+  return DesktopCapturer::Create(isolate(), show_screens, show_windows);
+}
+
 gfx::Point Screen::GetCursorScreenPoint() {
   return screen_->GetCursorScreenPoint();
 }
@@ -107,7 +122,8 @@ mate::ObjectTemplateBuilder Screen::GetObjectTemplateBuilder(
       .SetMethod("getPrimaryDisplay", &Screen::GetPrimaryDisplay)
       .SetMethod("getAllDisplays", &Screen::GetAllDisplays)
       .SetMethod("getDisplayNearestPoint", &Screen::GetDisplayNearestPoint)
-      .SetMethod("getDisplayMatching", &Screen::GetDisplayMatching);
+      .SetMethod("getDisplayMatching", &Screen::GetDisplayMatching)
+      .SetMethod("getDesktopCapturer", &Screen::GetDesktopCapturer);
 }
 
 // static

atom/browser/api/atom_api_screen.h

@@ -6,7 +6,9 @@
 #define ATOM_BROWSER_API_ATOM_API_SCREEN_H_
 
 #include <vector>
+#include <string>
 
+#include "atom/browser/api/atom_api_desktop_capturer.h"
 #include "atom/browser/api/event_emitter.h"
 #include "native_mate/handle.h"
 #include "ui/gfx/display_observer.h"
@@ -36,6 +38,9 @@ class Screen : public mate::EventEmitter,
   gfx::Display GetDisplayNearestPoint(const gfx::Point& point);
   gfx::Display GetDisplayMatching(const gfx::Rect& match_rect);
 
+  mate::Handle<DesktopCapturer> GetDesktopCapturer(
+      const std::vector<std::string>& sources);
+
   // gfx::DisplayObserver:
   void OnDisplayAdded(const gfx::Display& new_display) override;
   void OnDisplayRemoved(const gfx::Display& old_display) override;

atom/browser/api/lib/app.coffee

@@ -3,17 +3,18 @@ EventEmitter = require('events').EventEmitter
 bindings = process.atomBinding 'app'
 sessionBindings = process.atomBinding 'session'
 downloadItemBindings = process.atomBinding 'download_item'
+desktopCapturerBindings = process.atomBinding 'desktop_capturer'
 
 app = bindings.app
 app.__proto__ = EventEmitter.prototype
 
-wrapSession = (session) ->
-  # session is an Event Emitter.
-  session.__proto__ = EventEmitter.prototype
+wrapToEventListener = (item) ->
+  # item is an Event Emitter.
+  item.__proto__ = EventEmitter.prototype
 
 wrapDownloadItem = (download_item) ->
   # download_item is an Event Emitter.
-  download_item.__proto__ = EventEmitter.prototype
+  wrapToEventListener download_item
   # Be compatible with old APIs.
   download_item.url = download_item.getUrl()
   download_item.filename = download_item.getFilename()
@@ -58,11 +59,14 @@ app.resolveProxy = -> @defaultSession.resolveProxy.apply @defaultSession, argume
 app.on 'activate', (event, hasVisibleWindows) -> @emit 'activate-with-no-open-windows' if not hasVisibleWindows
 
 # Session wrapper.
-sessionBindings._setWrapSession wrapSession
+sessionBindings._setWrapSession wrapToEventListener
 process.once 'exit', sessionBindings._clearWrapSession
 
 downloadItemBindings._setWrapDownloadItem wrapDownloadItem
 process.once 'exit', downloadItemBindings._clearWrapDownloadItem
 
+desktopCapturerBindings._setWrapDesktopCapturer wrapToEventListener
+process.once 'exit', desktopCapturerBindings._clearWrapDesktopCapturer
+
 # Only one App object pemitted.
 module.exports = app

atom/common/node_bindings.cc

@@ -34,6 +34,7 @@ REFERENCE_MODULE(atom_browser_app);
 REFERENCE_MODULE(atom_browser_auto_updater);
 REFERENCE_MODULE(atom_browser_content_tracing);
 REFERENCE_MODULE(atom_browser_dialog);
+REFERENCE_MODULE(atom_browser_desktop_capturer);
 REFERENCE_MODULE(atom_browser_download_item);
 REFERENCE_MODULE(atom_browser_menu);
 REFERENCE_MODULE(atom_browser_power_monitor);

chromium_src/chrome/browser/media/desktop_media_list.h

@@ -0,0 +1,60 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_H_
+#define CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_H_
+
+#include "base/basictypes.h"
+#include "base/time/time.h"
+#include "content/public/browser/desktop_media_id.h"
+#include "ui/gfx/image/image_skia.h"
+
+class DesktopMediaListObserver;
+
+// DesktopMediaList provides the list of desktop media source (screens, windows,
+// tabs), and their thumbnails, to the desktop media picker dialog. It
+// transparently updates the list in the background, and notifies the desktop
+// media picker when something changes.
+class DesktopMediaList {
+ public:
+  // Struct used to represent each entry in the list.
+  struct Source {
+    // Id of the source.
+    content::DesktopMediaID id;
+
+    // Name of the source that should be shown to the user.
+    base::string16 name;
+
+    // The thumbnail for the source.
+    gfx::ImageSkia thumbnail;
+  };
+
+  virtual ~DesktopMediaList() {}
+
+  // Sets time interval between updates. By default list of sources and their
+  // thumbnail are updated once per second. If called after StartUpdating() then
+  // it will take effect only after the next update.
+  virtual void SetUpdatePeriod(base::TimeDelta period) = 0;
+
+  // Sets size to which the thumbnails should be scaled. If called after
+  // StartUpdating() then some thumbnails may be still scaled to the old size
+  // until they are updated.
+  virtual void SetThumbnailSize(const gfx::Size& thumbnail_size) = 0;
+
+  // Sets ID of the hosting desktop picker dialog. The window with this ID will
+  // be filtered out from the list of sources.
+  virtual void SetViewDialogWindowId(content::DesktopMediaID::Id dialog_id) = 0;
+
+  // Starts updating the model. The model is initially empty, so OnSourceAdded()
+  // notifications will be generated for each existing source as it is
+  // enumerated. After the initial enumeration the model will be refreshed based
+  // on the update period, and notifications generated only for changes in the
+  // model.
+  virtual void StartUpdating(DesktopMediaListObserver* observer) = 0;
+
+  virtual int GetSourceCount() const = 0;
+  virtual const Source& GetSource(int index) const = 0;
+};
+
+#endif  // CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_H_

chromium_src/chrome/browser/media/desktop_media_list_observer.h

@@ -0,0 +1,22 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_OBSERVER_H_
+#define CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_OBSERVER_H_
+
+// Interface implemented by the desktop media picker dialog to receive
+// notifications about changes in DesktopMediaList.
+class DesktopMediaListObserver {
+ public:
+  virtual void OnSourceAdded(int index) = 0;
+  virtual void OnSourceRemoved(int index) = 0;
+  virtual void OnSourceMoved(int old_index, int new_index) = 0;
+  virtual void OnSourceNameChanged(int index) = 0;
+  virtual void OnSourceThumbnailChanged(int index) = 0;
+
+ protected:
+  virtual ~DesktopMediaListObserver() {}
+};
+
+#endif  // CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_OBSERVER_H_

chromium_src/chrome/browser/media/native_desktop_media_list.cc

@@ -0,0 +1,366 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/media/native_desktop_media_list.h"
+
+#include <map>
+#include <set>
+#include <sstream>
+
+#include "base/hash.h"
+#include "base/logging.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/media/desktop_media_list_observer.h"
+#include "content/public/browser/browser_thread.h"
+#include "media/base/video_util.h"
+#include "third_party/libyuv/include/libyuv/scale_argb.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
+#include "third_party/webrtc/modules/desktop_capture/screen_capturer.h"
+#include "third_party/webrtc/modules/desktop_capture/window_capturer.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/skia_util.h"
+
+using content::BrowserThread;
+using content::DesktopMediaID;
+
+namespace {
+
+// Update the list every second.
+const int kDefaultUpdatePeriod = 1000;
+
+// Returns a hash of a DesktopFrame content to detect when image for a desktop
+// media source has changed.
+uint32 GetFrameHash(webrtc::DesktopFrame* frame) {
+  int data_size = frame->stride() * frame->size().height();
+  return base::SuperFastHash(reinterpret_cast<char*>(frame->data()), data_size);
+}
+
+gfx::ImageSkia ScaleDesktopFrame(scoped_ptr<webrtc::DesktopFrame> frame,
+                                 gfx::Size size) {
+  gfx::Rect scaled_rect = media::ComputeLetterboxRegion(
+      gfx::Rect(0, 0, size.width(), size.height()),
+      gfx::Size(frame->size().width(), frame->size().height()));
+
+  SkBitmap result;
+  result.allocN32Pixels(scaled_rect.width(), scaled_rect.height(), true);
+  result.lockPixels();
+
+  uint8* pixels_data = reinterpret_cast<uint8*>(result.getPixels());
+  libyuv::ARGBScale(frame->data(), frame->stride(),
+                    frame->size().width(), frame->size().height(),
+                    pixels_data, result.rowBytes(),
+                    scaled_rect.width(), scaled_rect.height(),
+                    libyuv::kFilterBilinear);
+
+  // Set alpha channel values to 255 for all pixels.
+  // TODO(sergeyu): Fix screen/window capturers to capture alpha channel and
+  // remove this code. Currently screen/window capturers (at least some
+  // implementations) only capture R, G and B channels and set Alpha to 0.
+  // crbug.com/264424
+  for (int y = 0; y < result.height(); ++y) {
+    for (int x = 0; x < result.width(); ++x) {
+      pixels_data[result.rowBytes() * y + x * result.bytesPerPixel() + 3] =
+          0xff;
+    }
+  }
+
+  result.unlockPixels();
+
+  return gfx::ImageSkia::CreateFrom1xBitmap(result);
+}
+
+}  // namespace
+
+NativeDesktopMediaList::SourceDescription::SourceDescription(
+    DesktopMediaID id,
+    const base::string16& name)
+    : id(id),
+      name(name) {
+}
+
+class NativeDesktopMediaList::Worker
+    : public webrtc::DesktopCapturer::Callback {
+ public:
+  Worker(base::WeakPtr<NativeDesktopMediaList> media_list,
+         scoped_ptr<webrtc::ScreenCapturer> screen_capturer,
+         scoped_ptr<webrtc::WindowCapturer> window_capturer);
+  ~Worker() override;
+
+  void Refresh(const gfx::Size& thumbnail_size,
+               content::DesktopMediaID::Id view_dialog_id);
+
+ private:
+  typedef std::map<DesktopMediaID, uint32> ImageHashesMap;
+
+  // webrtc::DesktopCapturer::Callback interface.
+  webrtc::SharedMemory* CreateSharedMemory(size_t size) override;
+  void OnCaptureCompleted(webrtc::DesktopFrame* frame) override;
+
+  base::WeakPtr<NativeDesktopMediaList> media_list_;
+
+  scoped_ptr<webrtc::ScreenCapturer> screen_capturer_;
+  scoped_ptr<webrtc::WindowCapturer> window_capturer_;
+
+  scoped_ptr<webrtc::DesktopFrame> current_frame_;
+
+  ImageHashesMap image_hashes_;
+
+  DISALLOW_COPY_AND_ASSIGN(Worker);
+};
+
+NativeDesktopMediaList::Worker::Worker(
+    base::WeakPtr<NativeDesktopMediaList> media_list,
+    scoped_ptr<webrtc::ScreenCapturer> screen_capturer,
+    scoped_ptr<webrtc::WindowCapturer> window_capturer)
+    : media_list_(media_list),
+      screen_capturer_(screen_capturer.Pass()),
+      window_capturer_(window_capturer.Pass()) {
+  if (screen_capturer_)
+    screen_capturer_->Start(this);
+  if (window_capturer_)
+    window_capturer_->Start(this);
+}
+
+NativeDesktopMediaList::Worker::~Worker() {}
+
+void NativeDesktopMediaList::Worker::Refresh(
+    const gfx::Size& thumbnail_size,
+    content::DesktopMediaID::Id view_dialog_id) {
+  std::vector<SourceDescription> sources;
+
+  if (screen_capturer_) {
+    webrtc::ScreenCapturer::ScreenList screens;
+    if (screen_capturer_->GetScreenList(&screens)) {
+      bool mutiple_screens = screens.size() > 1;
+      base::string16 title;
+      for (size_t i = 0; i < screens.size(); ++i) {
+        if (mutiple_screens) {
+          title = base::UTF8ToUTF16("Screen " + base::IntToString(i+1));
+        } else {
+          title = base::UTF8ToUTF16("Entire screen");
+        }
+        sources.push_back(SourceDescription(DesktopMediaID(
+            DesktopMediaID::TYPE_SCREEN, screens[i].id), title));
+      }
+    }
+  }
+
+  if (window_capturer_) {
+    webrtc::WindowCapturer::WindowList windows;
+    if (window_capturer_->GetWindowList(&windows)) {
+      for (webrtc::WindowCapturer::WindowList::iterator it = windows.begin();
+           it != windows.end(); ++it) {
+        // Skip the picker dialog window.
+        if (it->id != view_dialog_id) {
+          sources.push_back(SourceDescription(
+              DesktopMediaID(DesktopMediaID::TYPE_WINDOW, it->id),
+              base::UTF8ToUTF16(it->title)));
+        }
+      }
+    }
+  }
+  // Update list of windows before updating thumbnails.
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&NativeDesktopMediaList::OnSourcesList,
+                 media_list_, sources));
+
+  ImageHashesMap new_image_hashes;
+
+  // Get a thumbnail for each source.
+  for (size_t i = 0; i < sources.size(); ++i) {
+    SourceDescription& source = sources[i];
+    switch (source.id.type) {
+      case DesktopMediaID::TYPE_SCREEN:
+        if (!screen_capturer_->SelectScreen(source.id.id))
+          continue;
+        screen_capturer_->Capture(webrtc::DesktopRegion());
+        break;
+
+      case DesktopMediaID::TYPE_WINDOW:
+        if (!window_capturer_->SelectWindow(source.id.id))
+          continue;
+        window_capturer_->Capture(webrtc::DesktopRegion());
+        break;
+
+      default:
+        NOTREACHED();
+    }
+
+    // Expect that DesktopCapturer to always captures frames synchronously.
+    // |current_frame_| may be NULL if capture failed (e.g. because window has
+    // been closed).
+    if (current_frame_) {
+      uint32 frame_hash = GetFrameHash(current_frame_.get());
+      new_image_hashes[source.id] = frame_hash;
+
+      // Scale the image only if it has changed.
+      ImageHashesMap::iterator it = image_hashes_.find(source.id);
+      if (it == image_hashes_.end() || it->second != frame_hash) {
+        gfx::ImageSkia thumbnail =
+            ScaleDesktopFrame(current_frame_.Pass(), thumbnail_size);
+        BrowserThread::PostTask(
+            BrowserThread::UI, FROM_HERE,
+            base::Bind(&NativeDesktopMediaList::OnSourceThumbnail,
+                        media_list_, i, thumbnail));
+      }
+    }
+  }
+
+  image_hashes_.swap(new_image_hashes);
+
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&NativeDesktopMediaList::OnRefreshFinished, media_list_));
+}
+
+webrtc::SharedMemory* NativeDesktopMediaList::Worker::CreateSharedMemory(
+    size_t size) {
+  return NULL;
+}
+
+void NativeDesktopMediaList::Worker::OnCaptureCompleted(
+    webrtc::DesktopFrame* frame) {
+  current_frame_.reset(frame);
+}
+
+NativeDesktopMediaList::NativeDesktopMediaList(
+    scoped_ptr<webrtc::ScreenCapturer> screen_capturer,
+    scoped_ptr<webrtc::WindowCapturer> window_capturer)
+    : screen_capturer_(screen_capturer.Pass()),
+      window_capturer_(window_capturer.Pass()),
+      update_period_(base::TimeDelta::FromMilliseconds(kDefaultUpdatePeriod)),
+      thumbnail_size_(100, 100),
+      view_dialog_id_(-1),
+      observer_(NULL),
+      weak_factory_(this) {
+  base::SequencedWorkerPool* worker_pool = BrowserThread::GetBlockingPool();
+  capture_task_runner_ = worker_pool->GetSequencedTaskRunner(
+      worker_pool->GetSequenceToken());
+}
+
+NativeDesktopMediaList::~NativeDesktopMediaList() {
+  capture_task_runner_->DeleteSoon(FROM_HERE, worker_.release());
+}
+
+void NativeDesktopMediaList::SetUpdatePeriod(base::TimeDelta period) {
+  DCHECK(!observer_);
+  update_period_ = period;
+}
+
+void NativeDesktopMediaList::SetThumbnailSize(
+    const gfx::Size& thumbnail_size) {
+  thumbnail_size_ = thumbnail_size;
+}
+
+void NativeDesktopMediaList::SetViewDialogWindowId(
+    content::DesktopMediaID::Id dialog_id) {
+  view_dialog_id_ = dialog_id;
+}
+
+void NativeDesktopMediaList::StartUpdating(DesktopMediaListObserver* observer) {
+  DCHECK(!observer_);
+  DCHECK(screen_capturer_ || window_capturer_);
+
+  observer_ = observer;
+
+  worker_.reset(new Worker(weak_factory_.GetWeakPtr(),
+                           screen_capturer_.Pass(), window_capturer_.Pass()));
+  Refresh();
+}
+
+int NativeDesktopMediaList::GetSourceCount() const {
+  return sources_.size();
+}
+
+const DesktopMediaList::Source& NativeDesktopMediaList::GetSource(
+    int index) const {
+  return sources_[index];
+}
+
+void NativeDesktopMediaList::Refresh() {
+  capture_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&Worker::Refresh, base::Unretained(worker_.get()),
+                            thumbnail_size_, view_dialog_id_));
+}
+
+void NativeDesktopMediaList::OnSourcesList(
+    const std::vector<SourceDescription>& new_sources) {
+  typedef std::set<content::DesktopMediaID> SourceSet;
+  SourceSet new_source_set;
+  for (size_t i = 0; i < new_sources.size(); ++i) {
+    new_source_set.insert(new_sources[i].id);
+  }
+  // Iterate through the old sources to find the removed sources.
+  for (size_t i = 0; i < sources_.size(); ++i) {
+    if (new_source_set.find(sources_[i].id) == new_source_set.end()) {
+      sources_.erase(sources_.begin() + i);
+      observer_->OnSourceRemoved(i);
+      --i;
+    }
+  }
+  // Iterate through the new sources to find the added sources.
+  if (new_sources.size() > sources_.size()) {
+    SourceSet old_source_set;
+    for (size_t i = 0; i < sources_.size(); ++i) {
+      old_source_set.insert(sources_[i].id);
+    }
+
+    for (size_t i = 0; i < new_sources.size(); ++i) {
+      if (old_source_set.find(new_sources[i].id) == old_source_set.end()) {
+        sources_.insert(sources_.begin() + i, Source());
+        sources_[i].id = new_sources[i].id;
+        sources_[i].name = new_sources[i].name;
+        observer_->OnSourceAdded(i);
+      }
+    }
+  }
+  DCHECK_EQ(new_sources.size(), sources_.size());
+
+  // Find the moved/changed sources.
+  size_t pos = 0;
+  while (pos < sources_.size()) {
+    if (!(sources_[pos].id == new_sources[pos].id)) {
+      // Find the source that should be moved to |pos|, starting from |pos + 1|
+      // of |sources_|, because entries before |pos| should have been sorted.
+      size_t old_pos = pos + 1;
+      for (; old_pos < sources_.size(); ++old_pos) {
+        if (sources_[old_pos].id == new_sources[pos].id)
+          break;
+      }
+      DCHECK(sources_[old_pos].id == new_sources[pos].id);
+
+      // Move the source from |old_pos| to |pos|.
+      Source temp = sources_[old_pos];
+      sources_.erase(sources_.begin() + old_pos);
+      sources_.insert(sources_.begin() + pos, temp);
+
+      observer_->OnSourceMoved(old_pos, pos);
+    }
+
+    if (sources_[pos].name != new_sources[pos].name) {
+      sources_[pos].name = new_sources[pos].name;
+      observer_->OnSourceNameChanged(pos);
+    }
+    ++pos;
+  }
+}
+
+void NativeDesktopMediaList::OnSourceThumbnail(
+    int index,
+    const gfx::ImageSkia& image) {
+  DCHECK_LT(index, static_cast<int>(sources_.size()));
+  sources_[index].thumbnail = image;
+  observer_->OnSourceThumbnailChanged(index);
+}
+
+void NativeDesktopMediaList::OnRefreshFinished() {
+  BrowserThread::PostDelayedTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&NativeDesktopMediaList::Refresh,
+                 weak_factory_.GetWeakPtr()),
+      update_period_);
+}

chromium_src/chrome/browser/media/native_desktop_media_list.h

@@ -0,0 +1,100 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_NATIVE_DESKTOP_MEDIA_LIST_H_
+#define CHROME_BROWSER_MEDIA_NATIVE_DESKTOP_MEDIA_LIST_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/sequenced_task_runner.h"
+#include "chrome/browser/media/desktop_media_list.h"
+#include "content/public/browser/desktop_media_id.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace webrtc {
+class ScreenCapturer;
+class WindowCapturer;
+}
+
+// Implementation of DesktopMediaList that shows native screens and
+// native windows.
+class NativeDesktopMediaList : public DesktopMediaList {
+ public:
+  // Caller may pass NULL for either of the arguments in case when only some
+  // types of sources the model should be populated with (e.g. it will only
+  // contain windows, if |screen_capturer| is NULL).
+  NativeDesktopMediaList(
+      scoped_ptr<webrtc::ScreenCapturer> screen_capturer,
+      scoped_ptr<webrtc::WindowCapturer> window_capturer);
+  ~NativeDesktopMediaList() override;
+
+  // DesktopMediaList interface.
+  void SetUpdatePeriod(base::TimeDelta period) override;
+  void SetThumbnailSize(const gfx::Size& thumbnail_size) override;
+  void StartUpdating(DesktopMediaListObserver* observer) override;
+  int GetSourceCount() const override;
+  const Source& GetSource(int index) const override;
+  void SetViewDialogWindowId(content::DesktopMediaID::Id dialog_id) override;
+
+ private:
+  class Worker;
+  friend class Worker;
+
+  // Struct used to represent sources list the model gets from the Worker.
+  struct SourceDescription {
+    SourceDescription(content::DesktopMediaID id, const base::string16& name);
+
+    content::DesktopMediaID id;
+    base::string16 name;
+  };
+
+  // Order comparator for sources. Used to sort list of sources.
+  static bool CompareSources(const SourceDescription& a,
+                             const SourceDescription& b);
+
+  // Post a task for the |worker_| to update list of windows and get thumbnails.
+  void Refresh();
+
+  // Called by |worker_| to refresh the model. First it posts tasks for
+  // OnSourcesList() with the fresh list of sources, then follows with
+  // OnSourceThumbnail() for each changed thumbnail and then calls
+  // OnRefreshFinished() at the end.
+  void OnSourcesList(const std::vector<SourceDescription>& sources);
+  void OnSourceThumbnail(int index, const gfx::ImageSkia& thumbnail);
+  void OnRefreshFinished();
+
+  // Capturers specified in SetCapturers() and passed to the |worker_| later.
+  scoped_ptr<webrtc::ScreenCapturer> screen_capturer_;
+  scoped_ptr<webrtc::WindowCapturer> window_capturer_;
+
+  // Time interval between mode updates.
+  base::TimeDelta update_period_;
+
+  // Size of thumbnails generated by the model.
+  gfx::Size thumbnail_size_;
+
+  // ID of the hosting dialog.
+  content::DesktopMediaID::Id view_dialog_id_;
+
+  // The observer passed to StartUpdating().
+  DesktopMediaListObserver* observer_;
+
+  // Task runner used for the |worker_|.
+  scoped_refptr<base::SequencedTaskRunner> capture_task_runner_;
+
+  // An object that does all the work of getting list of sources on a background
+  // thread (see |capture_task_runner_|). Destroyed on |capture_task_runner_|
+  // after the model is destroyed.
+  scoped_ptr<Worker> worker_;
+
+  // Current list of sources.
+  std::vector<Source> sources_;
+
+  base::WeakPtrFactory<NativeDesktopMediaList> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativeDesktopMediaList);
+};
+
+#endif  // CHROME_BROWSER_MEDIA_NATIVE_DESKTOP_MEDIA_LIST_H_

filenames.gypi

@@ -71,6 +71,8 @@
       'atom/browser/api/atom_api_content_tracing.cc',
       'atom/browser/api/atom_api_cookies.cc',
       'atom/browser/api/atom_api_cookies.h',
+      'atom/browser/api/atom_api_desktop_capturer.cc',
+      'atom/browser/api/atom_api_desktop_capturer.h',
       'atom/browser/api/atom_api_download_item.cc',
       'atom/browser/api/atom_api_download_item.h',
       'atom/browser/api/atom_api_dialog.cc',
@@ -349,6 +351,10 @@
       'chromium_src/chrome/browser/extensions/global_shortcut_listener_x11.h',
       'chromium_src/chrome/browser/extensions/global_shortcut_listener_win.cc',
       'chromium_src/chrome/browser/extensions/global_shortcut_listener_win.h',
+      'chromium_src/chrome/browser/media/desktop_media_list.h',
+      'chromium_src/chrome/browser/media/desktop_media_list_observer.h',
+      'chromium_src/chrome/browser/media/native_desktop_media_list.cc',
+      'chromium_src/chrome/browser/media/native_desktop_media_list.h',
       'chromium_src/chrome/browser/printing/print_job.cc',
       'chromium_src/chrome/browser/printing/print_job.h',
       'chromium_src/chrome/browser/printing/print_job_manager.cc',