Use webrtc::DesktopCapturer for screen capturer implementation.

media/video/capture/screen/screen_capturer.h

Index: media/video/capture/screen/screen_capturer.h
diff --git a/media/video/capture/screen/screen_capturer.h b/media/video/capture/screen/screen_capturer.h
index bc3d454e945971b618a25ae8c753c120d7a3d911..5fef2a1ad159d750fa6928a03998e07af4ca1091 100644
--- a/media/video/capture/screen/screen_capturer.h
+++ b/media/video/capture/screen/screen_capturer.h
@@ -8,15 +8,12 @@
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
-#include "base/shared_memory.h"
 #include "media/base/media_export.h"
-#include "media/video/capture/screen/shared_buffer.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_capturer.h"
 
 namespace media {
 
-class ScreenCaptureData;
 struct MouseCursorShape;
-class SharedBuffer;
 
 // Class used to capture video frames asynchronously.
 //
@@ -36,32 +33,22 @@ class SharedBuffer;
 // Implementation has to ensure the following guarantees:
 // 1. Double buffering
 //    Since data can be read while another capture action is happening.
-class MEDIA_EXPORT ScreenCapturer {
+class MEDIA_EXPORT ScreenCapturer
+    : public NON_EXPORTED_BASE(webrtc::DesktopCapturer) {
  public:
   // Provides callbacks used by the capturer to pass captured video frames and
   // mouse cursor shapes to the processing pipeline.
-  class MEDIA_EXPORT Delegate {
+  //
+  // TODO(sergeyu): Move cursor shape capturing to a separate class because it's
+  // unrelated.
+  class MEDIA_EXPORT MouseShapeObserver {
    public:
-    // Creates a shared memory buffer of the given size. Returns NULL if shared
-    // buffers are not supported.
-    virtual scoped_refptr<SharedBuffer> CreateSharedBuffer(uint32 size);
-
-    // Notifies the delegate that the buffer is no longer used and can be
-    // released.
-    virtual void ReleaseSharedBuffer(scoped_refptr<SharedBuffer> buffer);
-
-    // Called when a video frame has been captured. |capture_data| describes
-    // a captured frame.
-    virtual void OnCaptureCompleted(
-        scoped_refptr<ScreenCaptureData> capture_data) = 0;
-
     // Called when the cursor shape has changed.
-    // TODO(sergeyu): Move cursor shape capturing to a separate class.
     virtual void OnCursorShapeChanged(
         scoped_ptr<MouseCursorShape> cursor_shape) = 0;
 
    protected:
-    virtual ~Delegate() {}
+    virtual ~MouseShapeObserver() {}
   };
 
   virtual ~ScreenCapturer() {}
@@ -77,20 +64,12 @@ class MEDIA_EXPORT ScreenCapturer {
   // Creates Windows-specific capturer and instructs it whether or not to
   // disable desktop compositing.
   static scoped_ptr<ScreenCapturer> CreateWithDisableAero(bool disable_aero);
-#endif
-
-  // Called at the beginning of a capturing session. |delegate| must remain
-  // valid until Stop() is called.
-  virtual void Start(Delegate* delegate) = 0;
+#endif  // defined(OS_WIN)
 
-  // Captures the screen data associated with each of the accumulated
-  // dirty region. When the capture is complete, the delegate is notified even
-  // if the dirty region is empty.
-  //
-  // It is OK to call this method while another thread is reading
-  // data of the previous capture. There can be at most one concurrent read
-  // going on when this method is called.
-  virtual void CaptureFrame() = 0;
+  // Called at the beginning of a capturing session. |mouse_shape_observer| must
+  // remain valid until the capturer is destroyed.
+  virtual void SetMouseShapeObserver(
+      MouseShapeObserver* mouse_shape_observer) = 0;
 };
 
 }  // namespace media