Smart layer invalidation for LCD text.

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 "base/time.h"
 #include "cc/base/math_util.h"
@@ skipping 835 matching lines @@
       layer_tree_impl()->IsActiveTree() ? PendingTwin() : this;
   if (layer_tree_impl()->IsActiveTree() &&
       pending_layer->is_using_lcd_text_ == is_using_lcd_text_)
     return;
 
   // Further tiles created due to new tilings should be considered invalidated.
   pending_layer->invalidation_.Union(gfx::Rect(bounds()));
   pending_layer->is_using_lcd_text_ = is_using_lcd_text_;
   pending_layer->pile_ = PicturePileImpl::CreateFromOther(pending_layer->pile_,
                                                           is_using_lcd_text_);
-
-  // TODO(enne): if we tracked text regions, we could just invalidate those
-  // directly rather than tossing away every tile.
-  pending_layer->tilings_->Invalidate(gfx::Rect(bounds()));
+  pending_layer->tilings_->InvalidateTilesWithText();
 }
 
 void PictureLayerImpl::ResetRasterScale() {
   raster_page_scale_ = 0.f;
   raster_device_scale_ = 0.f;
   raster_source_scale_ = 0.f;
   raster_contents_scale_ = 0.f;
   low_res_raster_contents_scale_ = 0.f;
 }
 
 void PictureLayerImpl::GetDebugBorderProperties(
     SkColor* color,
     float* width) const {
   *color = DebugColors::TiledContentLayerBorderColor();
   *width = DebugColors::TiledContentLayerBorderWidth(layer_tree_impl());
 }
 
 scoped_ptr<base::Value> PictureLayerImpl::AsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   LayerImpl::AsValueInto(state.get());
 
   state->SetDouble("ideal_contents_scale", ideal_contents_scale_);
   state->Set("tilings", tilings_->AsValue().release());
   return state.PassAs<base::Value>();
 }
 
 }  // namespace cc