cc: Calculate "can use lcd text" on the compositor thread

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 4093c425eb19541fc3a05651e0318a13c1313eed..8274f00c98a170e1e429deea801bbd98772df5e0 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -534,7 +534,7 @@ void LayerTreeImpl::ClearViewportLayers() {
   outer_viewport_scroll_layer_ = NULL;
 }
 
-bool LayerTreeImpl::UpdateDrawProperties() {
+bool LayerTreeImpl::UpdateDrawProperties(bool update_lcd_text) {
   if (!needs_update_draw_properties_)
     return true;
 
@@ -647,6 +647,25 @@ bool LayerTreeImpl::UpdateDrawProperties() {
         occlusion_tracker.ComputeVisibleRegionInScreen();
   }
 
+  // It'd be ideal if this could be done earlier, but when the raster source
+  // is updated from the main thread during push properties, update draw
+  // properties has not occurred yet and so it's not clear whether or not the
+  // layer can or cannot use lcd text.  So, this is the cleanup pass to
+  // determine if the raster source needs to be replaced with a non-lcd
+  // raster source due to draw properties.
+  if (update_lcd_text) {
+    // TODO(enne): Make LTHI::sync_tree return this value.
+    LayerTreeImpl* sync_tree =
+        layer_tree_host_impl_->proxy()->CommitToActiveTree()
+            ? layer_tree_host_impl_->active_tree()
+            : layer_tree_host_impl_->pending_tree();
+    // If this is not the sync tree, then it is not safe to update lcd text
+    // as it causes invalidations and the tiles may be in use.
+    DCHECK_EQ(this, sync_tree);
+    for (const auto& layer : picture_layers_)
+      layer->UpdateCanUseLCDTextAfterCommit();
+  }
+
   {
     TRACE_EVENT_BEGIN2("cc", "LayerTreeImpl::UpdateDrawProperties::UpdateTiles",
                        "IsActive", IsActiveTree(), "SourceFrameNumber",
@@ -859,6 +878,10 @@ bool LayerTreeImpl::IsRecycleTree() const {
   return layer_tree_host_impl_->recycle_tree() == this;
 }
 
+bool LayerTreeImpl::IsSyncTree() const {
+  return layer_tree_host_impl_->sync_tree() == this;
+}
+
 LayerImpl* LayerTreeImpl::FindActiveTreeLayerById(int id) {
   LayerTreeImpl* tree = layer_tree_host_impl_->active_tree();
   if (!tree)
@@ -1461,7 +1484,8 @@ LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPoint(
     const gfx::PointF& screen_space_point) {
   if (!root_layer())
     return NULL;
-  if (!UpdateDrawProperties())
+  bool update_lcd_text = false;
+  if (!UpdateDrawProperties(update_lcd_text))
     return NULL;
   FindClosestMatchingLayerDataForRecursion data_for_recursion;
   FindClosestMatchingLayer(screen_space_point,
@@ -1503,7 +1527,8 @@ LayerImpl* LayerTreeImpl::FindLayerWithWheelHandlerThatIsHitByPoint(
     const gfx::PointF& screen_space_point) {
   if (!root_layer())
     return NULL;
-  if (!UpdateDrawProperties())
+  bool update_lcd_text = false;
+  if (!UpdateDrawProperties(update_lcd_text))
     return NULL;
   FindWheelEventLayerFunctor func;
   FindClosestMatchingLayerDataForRecursion data_for_recursion;
@@ -1523,7 +1548,8 @@ LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPointInTouchHandlerRegion(
     const gfx::PointF& screen_space_point) {
   if (!root_layer())
     return NULL;
-  if (!UpdateDrawProperties())
+  bool update_lcd_text = false;
+  if (!UpdateDrawProperties(update_lcd_text))
     return NULL;
   FindTouchEventLayerFunctor func = {screen_space_point};
   FindClosestMatchingLayerDataForRecursion data_for_recursion;