Allow CopyFromBackingStore to fallback to copying from the renderer side if the accelerated surface…

content/browser/renderer_host/render_widget_host_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 
 #include <deque>
 #include <list>
 #include <map>
 #include <queue>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/process_util.h"
 #include "base/string16.h"
 #include "base/time.h"
 #include "base/timer.h"
@@ skipping 420 matching lines @@
 
   int SyntheticScrollMessageInterval() const;
 
   // Sets whether the overscroll controller should be enabled for this page.
   void SetOverscrollControllerEnabled(bool enabled);
 
   // Suppreses future char events until a keydown. See
   // suppress_next_char_events_.
   void SuppressNextCharEvents();
 
+  // Grab snapshot from renderer side. This can be used when copying from
+  // browser side might fail due to buggy drivers or other issues.

[Sam Kerner (Chrome), 2013/03/18 13:49:51]

Unless something changed, this should note that copying from the browser side
might fail because the browser side's cache has limited resources, and
intentionally discards images of tabs that are not visible and unused for a
while.

[justinlin, 2013/03/18 18:10:01]

I mentioned when the backing store is not available, which is more or less the
same issue.

As far as I can tell (after looking through the platform specific
CopyFromBackingStore's), it can't actually fail in the copy unless there's some
Skia issue.

+  void GetSnapshotFromRenderer(
+      const gfx::Rect& src_subrect,
+      const gfx::Size& dst_size,
+      const base::Callback<void(bool, const SkBitmap&)>& callback);
+
  protected:
   virtual RenderWidgetHostImpl* AsRenderWidgetHostImpl() OVERRIDE;
 
   // Transmits the given input event. This is an internal helper for
   // |ForwardInputEvent()| and should not be used directly from elsewhere.
   void SendInputEvent(const WebKit::WebInputEvent& input_event,
                       int event_size, bool is_keyboard_shortcut);
 
   // Internal implementation of the public Forward*Event() methods.
   void ForwardInputEvent(const WebKit::WebInputEvent& input_event,
@@ skipping 132 matching lines @@
   void OnUnlockMouse();
   void OnShowDisambiguationPopup(const gfx::Rect& rect,
                                  const gfx::Size& size,
                                  const TransportDIB::Id& id);
 #if defined(OS_WIN)
   void OnWindowlessPluginDummyWindowCreated(
       gfx::NativeViewId dummy_activation_window);
   void OnWindowlessPluginDummyWindowDestroyed(
       gfx::NativeViewId dummy_activation_window);
 #endif
+  void OnSnapshot(bool success, const SkBitmap& bitmap);
 
   // Called (either immediately or asynchronously) after we're done with our
   // BackingStore and can send an ACK to the renderer so it can paint onto it
   // again.
   void DidUpdateBackingStore(const ViewHostMsg_UpdateRect_Params& params,
                              const base::TimeTicks& paint_start);
 
   // Paints the given bitmap to the current backing store at the given
   // location.  Returns true if the passed callback was asynchronously
   // scheduled in the future (and thus the caller must manually synchronously
@@ skipping 235 matching lines @@
   typedef std::map<int, scoped_refptr<SmoothScrollGesture> >
       SmoothScrollGestureMap;
   SmoothScrollGestureMap active_smooth_scroll_gestures_;
   base::TimeTicks last_smooth_scroll_gestures_tick_time_;
   bool tick_active_smooth_scroll_gestures_task_posted_;
 
   scoped_ptr<TouchEventQueue> touch_event_queue_;
   scoped_ptr<GestureEventFilter> gesture_event_filter_;
   scoped_ptr<OverscrollController> overscroll_controller_;
 
+  typedef std::pair<gfx::Size, base::Callback<void(bool, const SkBitmap&)> >
+      PendingSnapshotInfo;
+  std::queue<PendingSnapshotInfo> pending_snapshots_;
+
 #if defined(OS_WIN)
   std::list<HWND> dummy_windows_for_activation_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_