cc: Fix lost context handling when using impl-side painting.

cc/picture_layer_impl.cc

 // Copyright 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.
 
 #include "cc/picture_layer_impl.h"
 
 #include "base/time.h"
 #include "cc/append_quads_data.h"
 #include "cc/checkerboard_draw_quad.h"
 #include "cc/debug_border_draw_quad.h"
@@ skipping 165 matching lines @@
   last_update_time_ = current_time;
   last_bounds_ = bounds();
   last_content_bounds_ = contentBounds();
   last_content_scale_ = contentsScaleX();
 }
 
 void PictureLayerImpl::didBecomeActive() {
   tilings_.MoveTilePriorities(PENDING_TREE, ACTIVE_TREE);
 }
 
+void PictureLayerImpl::didLoseOutputSurface() {
+  tilings_.RemoveAllTilings();
+}
+
 void PictureLayerImpl::calculateContentsScale(
     float ideal_contents_scale,
     float* contents_scale_x,
     float* contents_scale_y,
     gfx::Size* content_bounds) {
   if (!drawsContent()) {
     DCHECK(!tilings_.num_tilings());
     return;
   }
 
@@ skipping 246 matching lines @@
     if (std::find(used_tilings.begin(), used_tilings.end(), tiling) ==
         used_tilings.end())
       to_remove.push_back(tiling);
   }
 
   for (size_t i = 0; i < to_remove.size(); ++i)
     tilings_.Remove(to_remove[i]);
 }
 
 }  // namespace cc