Screen Video Capture: Implement suspend optimization.

media/capture/content/android/screen_capture_machine_android.h

 // Copyright 2016 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 MEDIA_CAPTURE_CONTENT_ANDROID_SCREEN_CAPTURE_MACHINE_ANDROID_H_
 #define MEDIA_CAPTURE_CONTENT_ANDROID_SCREEN_CAPTURE_MACHINE_ANDROID_H_
 
 #include <jni.h>
 #include <memory>
 
@@ skipping 37 matching lines @@
                             jint height,
                             jlong timestamp);
 
   // Implement org.chromium.media.ScreenCapture.nativeOnActivityResult.
   void OnActivityResult(JNIEnv* env, jobject obj, jboolean result);
 
   // VideoCaptureMachine overrides.
   void Start(const scoped_refptr<media::ThreadSafeCaptureOracle>& oracle_proxy,
              const media::VideoCaptureParams& params,
              const base::Callback<void(bool)> callback) override;
+  void Suspend() override;
+  void Resume() override;

[braveyao, 2016/09/26 17:14:47]

No definition to these two functions? 

[miu, 2016/09/27 20:46:50]

Oh no! Sorry, I missed that. Please see most recent patch set.

   void Stop(const base::Closure& callback) override;
   void MaybeCaptureForRefresh() override;
 
  private:
   // Makes all the decisions about which frames to copy, and how.
   scoped_refptr<media::ThreadSafeCaptureOracle> oracle_proxy_;
 
   // Cache the last frame for possible refreshing.
   scoped_refptr<VideoFrame> lastFrame_;
 
   // Java VideoCaptureAndroid instance.
   base::android::ScopedJavaLocalRef<jobject> j_capture_;
 
+  // True while frame capture has been suspended.
+  bool suspend_frame_capture_;

[braveyao, 2016/09/26 17:14:46]

Due to above comments, this variable is not used at all.

[miu, 2016/09/27 20:46:50]

It is now. ;)

+
   DISALLOW_COPY_AND_ASSIGN(ScreenCaptureMachineAndroid);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_CONTENT_ANDROID_SCREEN_CAPTURE_MACHINE_ANDROID_H_