Implement screen capture for android

content/browser/media/capture/content_video_capture_device_core.h

 // Copyright 2014 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 CONTENT_BROWSER_MEDIA_CAPTURE_CONTENT_VIDEO_CAPTURE_DEVICE_CORE_H_
 #define CONTENT_BROWSER_MEDIA_CAPTURE_CONTENT_VIDEO_CAPTURE_DEVICE_CORE_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 90 matching lines @@
   // Makes the decision to capture a frame.
   VideoCaptureOracle oracle_;
 
   // The video capture parameters used to construct the oracle proxy.
   const media::VideoCaptureParams params_;
 
   // The current video capture size.
   gfx::Size capture_size_;
 };
 
-// Keeps track of the video capture source frames and executes copying on the
-// UI BrowserThread.
+// Keeps track of the video capture source frames and executes copying.
 class VideoCaptureMachine {
  public:
   VideoCaptureMachine() {}
   virtual ~VideoCaptureMachine() {}
 
-  // Starts capturing. Returns true if succeeded.
-  // Must be run on the UI BrowserThread.
-  virtual bool Start(const scoped_refptr<ThreadSafeCaptureOracle>& oracle_proxy,
-                     const media::VideoCaptureParams& params) = 0;
+  // Starts capturing.
+  // |callback| is invoked with true if succeeded. Otherwise, with false.
+  virtual void Start(const scoped_refptr<ThreadSafeCaptureOracle>& oracle_proxy,
+                     const media::VideoCaptureParams& params,
+                     const base::Callback<void(bool)> callback) = 0;
 
-  // Stops capturing. Must be run on the UI BrowserThread.
+  // Stops capturing.
   // |callback| is invoked after the capturing has stopped.
   virtual void Stop(const base::Closure& callback) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureMachine);
 };
 
 // The "meat" of a content video capturer.
 //
 // Separating this from the "shell classes" WebContentsVideoCaptureDevice and
@@ skipping 32 matching lines @@
 
   // Stops capturing and notifies client_ of an error state.
   void Error(const std::string& reason);
 
   // Tracks that all activity occurs on the media stream manager's thread.
   base::ThreadChecker thread_checker_;
 
   // Current lifecycle state.
   State state_;
 
-  // Tracks the CaptureMachine that's doing work on our behalf on the UI thread.
-  // This value should never be dereferenced by this class, other than to
-  // create and destroy it on the UI thread.
+  // Tracks the CaptureMachine that's doing work on our behalf
+  // on the device thread or UI thread.
+  // This value should never be dereferenced by this class.
   scoped_ptr<VideoCaptureMachine> capture_machine_;
 
   // Our thread-safe capture oracle which serves as the gateway to the video
   // capture pipeline. Besides the VideoCaptureDevice itself, it is the only
   // component of the system with direct access to |client_|.
   scoped_refptr<ThreadSafeCaptureOracle> oracle_proxy_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentVideoCaptureDeviceCore);
 };
 
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_CAPTURE_CONTENT_VIDEO_CAPTURE_DEVICE_CORE_H_