Add a flag to disable partial raster in renderer

cc/layers/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/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <set>
@@ skipping 654 matching lines @@
   PictureLayerImpl* twin_layer = GetPendingOrActiveTwinLayer();
   if (!twin_layer)
     return nullptr;
   return twin_layer->tilings_->FindTilingWithScale(tiling->contents_scale());
 }
 
 bool PictureLayerImpl::RequiresHighResToDraw() const {
   return layer_tree_impl()->RequiresHighResToDraw();
 }
 
+bool PictureLayerImpl::EnablePartialRaster() const {
+  return layer_tree_impl()->settings().enable_partial_raster;
+}
+
 gfx::Rect PictureLayerImpl::GetEnclosingRectInTargetSpace() const {
   return GetScaledEnclosingRectInTargetSpace(MaximumTilingContentsScale());
 }
 
 gfx::Size PictureLayerImpl::CalculateTileSize(
     const gfx::Size& content_bounds) const {
   int max_texture_size =
       layer_tree_impl()->resource_provider()->max_texture_size();
 
   if (is_mask_) {
@@ skipping 561 matching lines @@
 
 bool PictureLayerImpl::IsOnActiveOrPendingTree() const {
   return !layer_tree_impl()->IsRecycleTree();
 }
 
 bool PictureLayerImpl::HasValidTilePriorities() const {
   return IsOnActiveOrPendingTree() && IsDrawnRenderSurfaceLayerListMember();
 }
 
 }  // namespace cc