Adding a unit test to verify the IPC channel between the network and desktop processes.

media/video/capture/screen/screen_capturer_fake.h

Index: media/video/capture/screen/screen_capturer_fake.h
diff --git a/media/video/capture/screen/screen_capturer_fake.h b/media/video/capture/screen/screen_capturer_fake.h
index 11daad49e301b85823ddf6a87e4d0fcd8dc71ce5..69f4dd1fa09aa1b12d0f7c638d759d55b2f29e81 100644
--- a/media/video/capture/screen/screen_capturer_fake.h
+++ b/media/video/capture/screen/screen_capturer_fake.h
@@ -50,11 +50,17 @@ class MEDIA_EXPORT ScreenCapturerFake : public ScreenCapturer {
 
   // We have two buffers for the screen images as required by Capturer.
   static const int kNumBuffers = 2;
-  scoped_array<uint8> buffers_[kNumBuffers];
+  uint8* buffers_[kNumBuffers];
 
   // The current buffer with valid data for reading.
   int current_buffer_;
 
+  // Used when |delegate_| implements CreateSharedBuffer().
+  scoped_refptr<SharedBuffer> shared_buffers_[kNumBuffers];
+
+  // Used when |delegate_| does not implement CreateSharedBuffer().
+  scoped_array<uint8> private_buffers_[kNumBuffers];
+
   DISALLOW_COPY_AND_ASSIGN(ScreenCapturerFake);
 };