cc: Allow output readback/copy requests to specify a sub-rect to copy.

cc/layers/layer_impl.cc

 // Copyright 2011 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/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/strings/stringprintf.h"
 #include "cc/animation/animation_registrar.h"
 #include "cc/animation/scrollbar_animation_controller.h"
@@ skipping 95 matching lines @@
 void LayerImpl::PassCopyRequests(ScopedPtrVector<CopyOutputRequest>* requests) {
   if (requests->empty())
     return;
 
   copy_requests_.insert_and_take(copy_requests_.end(), *requests);
   requests->clear();
 
   NoteLayerPropertyChangedForSubtree();
 }
 
-void LayerImpl::TakeCopyRequests(ScopedPtrVector<CopyOutputRequest>* requests) {
+void LayerImpl::TakeCopyRequestsAndTransformToTarget(
+    ScopedPtrVector<CopyOutputRequest>* requests) {
   if (copy_requests_.empty())
     return;
 
   requests->insert_and_take(requests->end(), copy_requests_);
   copy_requests_.clear();
+
+  for (size_t i = 0; i < requests->size(); ++i) {
+    CopyOutputRequest* request = requests->at(i);
+    if (!request->has_area())
+      continue;
+
+    gfx::Rect request_in_layer_space = request->area();
+    gfx::Rect request_in_content_space =
+        LayerRectToContentRect(request_in_layer_space);
+    request->set_area(
+        MathUtil::MapClippedRect(draw_properties_.target_space_transform,
+                                 request_in_content_space));
+  }
 }
 
 void LayerImpl::CreateRenderSurface() {
   DCHECK(!draw_properties_.render_surface);
   draw_properties_.render_surface =
       make_scoped_ptr(new RenderSurfaceImpl(this));
   draw_properties_.render_target = this;
 }
 
 void LayerImpl::ClearRenderSurface() {
@@ skipping 1036 matching lines @@
 
 size_t LayerImpl::GPUMemoryUsageInBytes() const { return 0; }
 
 scoped_ptr<base::Value> LayerImpl::AsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   AsValueInto(state.get());
   return state.PassAs<base::Value>();
 }
 
 }  // namespace cc