Revert "Revert 210138 "Perform glReadPixels with PBOs in the gpu, if PBO...""

cc/test/test_web_graphics_context_3d.h

Index: cc/test/test_web_graphics_context_3d.h
diff --git a/cc/test/test_web_graphics_context_3d.h b/cc/test/test_web_graphics_context_3d.h
index 41296b299c3abdc98ca3264daed6289b86bb0aa1..b182fe6559b3dad0090fa7eae0db7db171095aef 100644
--- a/cc/test/test_web_graphics_context_3d.h
+++ b/cc/test/test_web_graphics_context_3d.h
@@ -114,6 +114,8 @@ class TestWebGraphicsContext3D : public FakeWebGraphicsContext3D {
   // Takes ownership of the |callback|.
   virtual void signalSyncPoint(unsigned sync_point,
                                WebGraphicsSyncPointCallback* callback);
+  virtual void signalQuery(WebKit::WebGLId query,
+                           WebGraphicsSyncPointCallback* callback);
 
   virtual void setSwapBuffersCompleteCallbackCHROMIUM(
       WebGraphicsSwapBuffersCompleteCallbackCHROMIUM* callback);