Smart layer invalidation for LCD text.

cc/resources/picture_layer_tiling.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/resources/picture_layer_tiling.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/debug/trace_event.h"
@@ skipping 138 matching lines @@
 
       tiles_.erase(found);
       new_tiles.push_back(key);
     }
   }
 
   for (size_t i = 0; i < new_tiles.size(); ++i)
     CreateTile(new_tiles[i].first, new_tiles[i].second);
 }
 
+void PictureLayerTiling::InvalidateTilesWithText() {
+  std::vector<TileMapKey> new_tiles;
+  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
+    if (it->second->has_text())
+      new_tiles.push_back(it->first);
+  }
+
+  for (size_t i = 0; i < new_tiles.size(); ++i) {
+    tiles_.erase(new_tiles[i]);
+    CreateTile(new_tiles[i].first, new_tiles[i].second);
+  }
+}
+
 void PictureLayerTiling::CreateTilesFromLayerRect(gfx::Rect layer_rect) {
   gfx::Rect content_rect =
       gfx::ToEnclosingRect(ScaleRect(layer_rect, contents_scale_));
   CreateTilesFromContentRect(content_rect);
 }
 
 void PictureLayerTiling::CreateTilesFromContentRect(gfx::Rect content_rect) {
   for (TilingData::Iterator iter(&tiling_data_, content_rect); iter; ++iter) {
     TileMap::iterator found =
         tiles_.find(TileMapKey(iter.index_x(), iter.index_y()));
@@ skipping 439 matching lines @@
 
     // If our delta is less then our event distance, we're done.
     if (delta < event.distance)
       break;
   }
 
   return gfx::Rect(origin_x, origin_y, width, height);
 }
 
 }  // namespace cc