Implemented GetWindowSnapshot on RenderViewImpl

content/renderer/render_view_impl.h

Index: content/renderer/render_view_impl.h
diff --git a/content/renderer/render_view_impl.h b/content/renderer/render_view_impl.h
index 468c268f60e8b0d308f06e551c68259f67180087..5721e4231f08c63f96f559d9dd1e56babf5e76b4 100644
--- a/content/renderer/render_view_impl.h
+++ b/content/renderer/render_view_impl.h
@@ -365,6 +365,13 @@ class RenderViewImpl : public RenderWidget,
   // supported PPAPI plug-ins.
   bool HasIMETextFocus();
 
+  // Callback for use with GetWindowSnapshot.
+  typedef base::Callback<void(
+      const gfx::Size&, const std::vector<unsigned char>&)>
+      WindowSnapshotCallback;
+
+  void GetWindowSnapshot(const WindowSnapshotCallback& callback);
+
   // IPC::Listener implementation ----------------------------------------------
 
   virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
@@ -1022,6 +1029,9 @@ class RenderViewImpl : public RenderWidget,
                             const gfx::Rect& view_frame);
 #endif
 
+  void OnWindowSnapshotCompleted(const int snapshot_id,
+      const gfx::Size& size, const std::vector<unsigned char>& png);
+
 
   // Adding a new message handler? Please add it in alphabetical order above
   // and put it in the same position in the .cc file.
@@ -1494,6 +1504,12 @@ class RenderViewImpl : public RenderWidget,
   // Wraps the |webwidget_| as a MouseLockDispatcher::LockTarget interface.
   scoped_ptr<MouseLockDispatcher::LockTarget> webwidget_mouse_lock_target_;
 
+  // State associated with the GetWindowSnapshot function.
+  int next_snapshot_id_;
+  typedef std::map<int, WindowSnapshotCallback>
+      PendingSnapshotMap;
+  PendingSnapshotMap pending_snapshots_;
+
   // Plugins -------------------------------------------------------------------
 
   // All the currently active plugin delegates for this RenderView; kept so