cc: Reset raster scale if we didn't sync high res tiling.

cc/resources/picture_layer_tiling_set.cc

Index: cc/resources/picture_layer_tiling_set.cc
diff --git a/cc/resources/picture_layer_tiling_set.cc b/cc/resources/picture_layer_tiling_set.cc
index 47d393f19202e54d0f5c9a5a765b07eac52f1e47..d292d83fab2a53d05ba39d7ca579e3db11c2c0cc 100644
--- a/cc/resources/picture_layer_tiling_set.cc
+++ b/cc/resources/picture_layer_tiling_set.cc
@@ -36,15 +36,14 @@ void PictureLayerTilingSet::SetClient(PictureLayerTilingClient* client) {
     tilings_[i]->SetClient(client_);
 }
 
-void PictureLayerTilingSet::SyncTilings(
-    const PictureLayerTilingSet& other,
-    const gfx::Size& new_layer_bounds,
-    const Region& layer_invalidation,
-    float minimum_contents_scale) {
+bool PictureLayerTilingSet::SyncTilings(const PictureLayerTilingSet& other,
+                                        const gfx::Size& new_layer_bounds,
+                                        const Region& layer_invalidation,
+                                        float minimum_contents_scale) {
   if (new_layer_bounds.IsEmpty()) {
     RemoveAllTilings();
     layer_bounds_ = new_layer_bounds;
-    return;
+    return false;
   }
 
   tilings_.reserve(other.tilings_.size());
@@ -60,6 +59,8 @@ void PictureLayerTilingSet::SyncTilings(
     --i;
   }
 
+  bool have_high_res_tiling = false;
+
   // Add any missing tilings from |other| that meet the minimum.
   for (size_t i = 0; i < other.tilings_.size(); ++i) {
     float contents_scale = other.tilings_[i]->contents_scale();
@@ -75,6 +76,8 @@ void PictureLayerTilingSet::SyncTilings(
 
       this_tiling->UpdateTilesToCurrentPile();
       this_tiling->CreateMissingTilesInLiveTilesRect();
+      if (this_tiling->resolution() == HIGH_RESOLUTION)
+        have_high_res_tiling = true;
 
       DCHECK(this_tiling->tile_size() ==
              client_->CalculateTileSize(this_tiling->TilingRect().size()));
@@ -85,11 +88,14 @@ void PictureLayerTilingSet::SyncTilings(
         new_layer_bounds,
         client_);
     new_tiling->set_resolution(other.tilings_[i]->resolution());
+    if (new_tiling->resolution() == HIGH_RESOLUTION)
+      have_high_res_tiling = true;
     tilings_.push_back(new_tiling.Pass());
   }
   tilings_.sort(LargestToSmallestScaleFunctor());
 
   layer_bounds_ = new_layer_bounds;
+  return have_high_res_tiling;
 }
 
 void PictureLayerTilingSet::RemoveTilesInRegion(const Region& region) {