Declare a new name for CompositingSurface completion callback.

content/browser/renderer_host/render_widget_host_view_base.h

Index: content/browser/renderer_host/render_widget_host_view_base.h
diff --git a/content/browser/renderer_host/render_widget_host_view_base.h b/content/browser/renderer_host/render_widget_host_view_base.h
index 4da2b56416d704d6dba154a4c15ad07922ce3ea0..8d30de5cbc6f634461d01d7e4d1ef754ab8ee041 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -59,6 +59,11 @@ struct DidOverscrollParams;
 struct NativeWebKeyboardEvent;
 struct WebPluginGeometry;
 
+// TODO(Sikugu): Though we have the return status of the result here,
+// we should add the reason for failure as a new parameter to handle cases
+// efficiently.
+typedef const base::Callback<void(bool, const SkBitmap&)> CompletionCallback;

[piman, 2014/09/16 20:24:56]

Can we either expand the name, or scope it?

content::CompletionCallback doesn't convey the fact that it has to do with
CopyFromCompositingSurface, and is too generic to be in the content namespace.

How about content::CopyFromCompositingSurfaceCallback?

[sivag, 2014/09/17 11:17:11]

Done.

+
 // Basic implementation shared by concrete RenderWidgetHostView subclasses.
 class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
                                                 public IPC::Listener {
@@ -255,11 +260,10 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // copy is then scaled to a SkBitmap of size |dst_size|. |callback| is run
   // with true on success, false otherwise. A smaller region than |src_subrect|
   // may be copied if the underlying surface is smaller than |src_subrect|.
-  virtual void CopyFromCompositingSurface(
-      const gfx::Rect& src_subrect,
-      const gfx::Size& dst_size,
-      const base::Callback<void(bool, const SkBitmap&)>& callback,
-      const SkColorType color_type) = 0;
+  virtual void CopyFromCompositingSurface(const gfx::Rect& src_subrect,
+                                          const gfx::Size& dst_size,
+                                          CompletionCallback& callback,
+                                          const SkColorType color_type) = 0;
 
   // Copies the contents of the compositing surface, populating the given
   // |target| with YV12 image data. |src_subrect| is specified in layer space