feat: add desktopCapturer.getMediaSourceIdForWebContents() to get stream source id from web contents (#22701)

* feat: add desktopCapturer.getMediaSourceIdForWebContents() to get stream source id from web contents

* Cleanup from #22701 PR comments

shell/browser/api/electron_api_desktop_capturer.cc

@@ -14,7 +14,11 @@
 #include "chrome/browser/media/webrtc/desktop_media_list.h"
 #include "chrome/browser/media/webrtc/window_icon_util.h"
 #include "content/public/browser/desktop_capture.h"
+#include "content/public/browser/desktop_streams_registry.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
 #include "gin/object_template_builder.h"
+#include "shell/browser/api/electron_api_web_contents.h"
 #include "shell/common/api/electron_api_native_image.h"
 #include "shell/common/gin_converters/gfx_converter.h"
 #include "shell/common/gin_helper/dictionary.h"
@@ -22,6 +26,7 @@
 #include "shell/common/node_includes.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_capturer.h"
+#include "url/origin.h"
 
 #if defined(OS_WIN)
 #include "third_party/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h"
@@ -202,6 +207,55 @@ gin::Handle<DesktopCapturer> DesktopCapturer::Create(v8::Isolate* isolate) {
   return gin::CreateHandle(isolate, new DesktopCapturer(isolate));
 }
 
+// static
+std::string DesktopCapturer::GetMediaSourceIdForWebContents(
+    v8::Isolate* isolate,
+    gin_helper::ErrorThrower thrower,
+    int32_t request_web_contents_id,
+    int32_t web_contents_id) {
+  std::string id;
+  auto* web_contents = gin_helper::TrackableObject<WebContents>::FromWeakMapID(
+      isolate, web_contents_id);
+
+  if (!web_contents) {
+    thrower.ThrowError("Failed to find WebContents with id " +
+                       std::to_string(web_contents_id));
+    return id;
+  }
+
+  auto* main_frame = web_contents->web_contents()->GetMainFrame();
+  DCHECK(main_frame);
+  content::DesktopMediaID media_id(
+      content::DesktopMediaID::TYPE_WEB_CONTENTS,
+      content::DesktopMediaID::kNullId,
+      content::WebContentsMediaCaptureId(main_frame->GetProcess()->GetID(),
+                                         main_frame->GetRoutingID()));
+
+  auto* request_web_contents =
+      gin_helper::TrackableObject<WebContents>::FromWeakMapID(
+          isolate, request_web_contents_id);
+  if (request_web_contents) {
+    // comment copied from
+    // chrome/browser/extensions/api/desktop_capture/desktop_capture_base.cc
+    // TODO(miu): Once render_frame_host() is being set, we should register the
+    // exact RenderFrame requesting the stream, not the main RenderFrame.  With
+    // that change, also update
+    // MediaCaptureDevicesDispatcher::ProcessDesktopCaptureAccessRequest().
+    // http://crbug.com/304341
+    auto* const request_main_frame =
+        request_web_contents->web_contents()->GetMainFrame();
+    DCHECK(request_main_frame);
+    id = content::DesktopStreamsRegistry::GetInstance()->RegisterStream(
+        request_main_frame->GetProcess()->GetID(),
+        request_main_frame->GetRoutingID(),
+        url::Origin::Create(
+            request_main_frame->GetLastCommittedURL().GetOrigin()),
+        media_id, "", content::kRegistryStreamTypeTab);
+  }
+
+  return id;
+}
+
 gin::ObjectTemplateBuilder DesktopCapturer::GetObjectTemplateBuilder(
     v8::Isolate* isolate) {
   return gin::Wrappable<DesktopCapturer>::GetObjectTemplateBuilder(isolate)
@@ -225,6 +279,9 @@ void Initialize(v8::Local<v8::Object> exports,
   gin_helper::Dictionary dict(context->GetIsolate(), exports);
   dict.SetMethod("createDesktopCapturer",
                  &electron::api::DesktopCapturer::Create);
+  dict.SetMethod(
+      "getMediaSourceIdForWebContents",
+      &electron::api::DesktopCapturer::GetMediaSourceIdForWebContents);
 }
 
 }  // namespace