refactor: desktop capturer module (#14835)

* Revert "post all desktop capturer apis to worker threads"

This reverts commit 5a28759fea.

* refactor: desktop capturer module

* Creates the screen and window capturer for the liftime of the app
* Fixes incorrect usage of weak ptr

* build: add //ui/snapshot to chromium_src deps

* fix: handle scenarios when there are no captured sources

patches/common/webrtc/.patches.yaml

@@ -1,13 +1,5 @@
 repo: src/third_party/webrtc
 patches:
--
-  author: null
-  file: webrtc-desktop_capturer_mac.patch
-  description: null
--
-  author: null
-  file: webrtc-rwlock_null.patch
-  description: null
 -
   author: Nitish Sakhawalkar <nitsakh@icloud.com>
   file: disable-warning-win.patch

patches/common/webrtc/webrtc-desktop_capturer_mac.patch

@@ -1,117 +0,0 @@
-diff --git a/modules/desktop_capture/mac/screen_capturer_mac.mm b/modules/desktop_capture/mac/screen_capturer_mac.mm
-index df18777226..6a1e3da6ab 100644
---- a/modules/desktop_capture/mac/screen_capturer_mac.mm
-+++ b/modules/desktop_capture/mac/screen_capturer_mac.mm
-@@ -16,6 +16,7 @@
- #include "rtc_base/checks.h"
- #include "rtc_base/constructormagic.h"
- #include "rtc_base/logging.h"
-+#include "rtc_base/synchronization/rw_lock_wrapper.h"
- #include "rtc_base/timeutils.h"
- #include "sdk/objc/Framework/Classes/Common/scoped_cftyperef.h"
- 
-@@ -28,18 +29,31 @@ namespace webrtc {
- // destroy itself once it's done.
- class DisplayStreamManager {
-  public:
--  int GetUniqueId() { return ++unique_id_generator_; }
--  void DestroyStream(int unique_id) {
--    auto it = display_stream_wrappers_.find(unique_id);
--    RTC_CHECK(it != display_stream_wrappers_.end());
--    RTC_CHECK(!it->second.active);
--    CFRelease(it->second.stream);
--    display_stream_wrappers_.erase(it);
-+  DisplayStreamManager() : rw_lock_(RWLockWrapper::CreateRWLock()) {}
-+  RWLockWrapper* GetLock() {return rw_lock_.get();};
- 
--    if (ready_for_self_destruction_ && display_stream_wrappers_.empty()) delete this;
-+  int GetUniqueId() {
-+    WriteLockScoped scoped_display_stream_manager_lock(*rw_lock_);
-+    return ++unique_id_generator_;
-+  }
-+  void DestroyStream(int unique_id) {
-+    bool finalize;
-+    {
-+      WriteLockScoped scoped_display_stream_manager_lock(*rw_lock_);
-+      auto it = display_stream_wrappers_.find(unique_id);
-+      RTC_CHECK(it != display_stream_wrappers_.end());
-+      RTC_CHECK(!it->second.active);
-+      CFRelease(it->second.stream);
-+      display_stream_wrappers_.erase(it);
-+      finalize = ready_for_self_destruction_ && display_stream_wrappers_.empty();
-+    }
-+    if (finalize) {
-+      delete this;
-+    }
-   }
- 
-   void SaveStream(int unique_id, CGDisplayStreamRef stream) {
-+    WriteLockScoped scoped_display_stream_manager_lock(*rw_lock_);
-     RTC_CHECK(unique_id <= unique_id_generator_);
-     DisplayStreamWrapper wrapper;
-     wrapper.stream = stream;
-@@ -47,6 +61,7 @@ class DisplayStreamManager {
-   }
- 
-   void UnregisterActiveStreams() {
-+    WriteLockScoped scoped_display_stream_manager_lock(*rw_lock_);
-     for (auto& pair : display_stream_wrappers_) {
-       DisplayStreamWrapper& wrapper = pair.second;
-       if (wrapper.active) {
-@@ -61,12 +76,23 @@ class DisplayStreamManager {
-   void PrepareForSelfDestruction() {
-     ready_for_self_destruction_ = true;
- 
--    if (display_stream_wrappers_.empty()) delete this;
-+    bool finalize;
-+    {
-+      WriteLockScoped scoped_display_stream_manager_lock(*rw_lock_);
-+      ready_for_self_destruction_ = true;
-+      finalize = display_stream_wrappers_.empty();
-+    }
-+    if (finalize) {
-+      delete this;
-+    }
-   }
- 
-   // Once the DisplayStreamManager is ready for destruction, the
-   // ScreenCapturerMac is no longer present. Any updates should be ignored.
--  bool ShouldIgnoreUpdates() { return ready_for_self_destruction_; }
-+  // Note: not thread-safe! Acquire and release a lock manually.
-+  bool ShouldIgnoreUpdates() {
-+     return ready_for_self_destruction_;
-+  }
- 
-  private:
-   struct DisplayStreamWrapper {
-@@ -81,6 +107,7 @@ class DisplayStreamManager {
-   std::map<int, DisplayStreamWrapper> display_stream_wrappers_;
-   int unique_id_generator_ = 0;
-   bool ready_for_self_destruction_ = false;
-+  std::unique_ptr<RWLockWrapper> rw_lock_;
- };
- 
- namespace {
-@@ -507,8 +534,6 @@ bool ScreenCapturerMac::RegisterRefreshAndMoveHandlers() {
-         return;
-       }
- 
--      if (manager->ShouldIgnoreUpdates()) return;
--
-       // Only pay attention to frame updates.
-       if (status != kCGDisplayStreamFrameStatusFrameComplete) return;
- 
-@@ -518,7 +543,12 @@ bool ScreenCapturerMac::RegisterRefreshAndMoveHandlers() {
-       if (count != 0) {
-         // According to CGDisplayStream.h, it's safe to call
-         // CGDisplayStreamStop() from within the callback.
--        ScreenRefresh(count, rects, display_origin);
-+        manager->GetLock()->AcquireLockShared();
-+        bool screen_capturer_mac_invalidated = manager->ShouldIgnoreUpdates();
-+        if (!screen_capturer_mac_invalidated) {
-+          ScreenRefresh(count, rects, display_origin);
-+        }
-+        manager->GetLock()->ReleaseLockShared();
-       }
-     };
- 

patches/common/webrtc/webrtc-rwlock_null.patch

@@ -1,36 +0,0 @@
-diff --git a/rtc_base/synchronization/rw_lock_wrapper.cc b/rtc_base/synchronization/rw_lock_wrapper.cc
-index c8cd17edb8..50c6e25ad9 100644
---- a/rtc_base/synchronization/rw_lock_wrapper.cc
-+++ b/rtc_base/synchronization/rw_lock_wrapper.cc
-@@ -11,6 +11,9 @@
- #include "rtc_base/synchronization/rw_lock_wrapper.h"
- 
- #include <assert.h>
-+#include <stdlib.h>
-+
-+#include "system_wrappers/include/sleep.h"
- 
- #if defined(_WIN32)
- #include "rtc_base/synchronization/rw_lock_win.h"
-@@ -21,11 +23,19 @@
- namespace webrtc {
- 
- RWLockWrapper* RWLockWrapper::CreateRWLock() {
-+  RWLockWrapper* rw_lock_ptr;
- #ifdef _WIN32
--  return RWLockWin::Create();
-+  rw_lock_ptr = RWLockWin::Create();
- #else
--  return RWLockPosix::Create();
-+  rw_lock_ptr = RWLockPosix::Create();
- #endif
-+  if (rw_lock_ptr != NULL) {
-+    return rw_lock_ptr;
-+  } else {
-+    int msec_wait = 10 + (rand() % 90);
-+    SleepMs(msec_wait);
-+    return CreateRWLock();
-+  }
- }
- 
- }  // namespace webrtc