Reland of rewrite frame generator capturer to use TaskQueue instead of EventTimeWrapper

webrtc/test/frame_generator_capturer.h

Index: webrtc/test/frame_generator_capturer.h
diff --git a/webrtc/test/frame_generator_capturer.h b/webrtc/test/frame_generator_capturer.h
index dfd12711d187988560178bc90082b1e4788d472f..75e48497bec35c65fa5a746e57e619c570c78b79 100644
--- a/webrtc/test/frame_generator_capturer.h
+++ b/webrtc/test/frame_generator_capturer.h
@@ -15,7 +15,7 @@
 
 #include "webrtc/api/video/video_frame.h"
 #include "webrtc/base/criticalsection.h"
-#include "webrtc/base/platform_thread.h"
+#include "webrtc/base/task_queue.h"
 #include "webrtc/test/video_capturer.h"
 #include "webrtc/typedefs.h"
 
@@ -74,6 +74,8 @@ class FrameGeneratorCapturer : public VideoCapturer {
   bool Init();
 
  private:
+  class InsertFrameTask;
+
   void InsertFrame();
   static bool Run(void* obj);
 
@@ -82,17 +84,18 @@ class FrameGeneratorCapturer : public VideoCapturer {
   rtc::VideoSinkInterface<VideoFrame>* sink_ GUARDED_BY(&lock_);
   SinkWantsObserver* sink_wants_observer_ GUARDED_BY(&lock_);
 
-  std::unique_ptr<EventTimerWrapper> tick_;
   rtc::CriticalSection lock_;
-  rtc::PlatformThread thread_;
   std::unique_ptr<FrameGenerator> frame_generator_;
 
   int target_fps_;
   VideoRotation fake_rotation_ = kVideoRotation_0;
 
   int64_t first_frame_capture_time_;
+  // Must be the last field, so it will be deconstructed first as tasks
+  // in the TaskQueue access other fields of the instance of this class.
+  rtc::TaskQueue task_queue_;
 };
-}  // test
-}  // webrtc
+}  // namespace test
+}  // namespace webrtc
 
 #endif  // WEBRTC_TEST_FRAME_GENERATOR_CAPTURER_H_