Make PageScaleFactor work for oopif subframes.

cc/trees/layer_tree.cc

Index: cc/trees/layer_tree.cc
diff --git a/cc/trees/layer_tree.cc b/cc/trees/layer_tree.cc
index 5f5e5519474168b9e55f8042c6ff3b599fdaeaa4..d0f0ac729254dd6123608ce838233149925afae5 100644
--- a/cc/trees/layer_tree.cc
+++ b/cc/trees/layer_tree.cc
@@ -26,6 +26,7 @@ LayerTree::Inputs::Inputs()
       device_scale_factor(1.f),
       painted_device_scale_factor(1.f),
       page_scale_factor(1.f),
+      subframe_page_scale_factor(1.f),
       min_page_scale_factor(1.f),
       max_page_scale_factor(1.f),
       background_color(SK_ColorWHITE),
@@ -174,6 +175,14 @@ void LayerTree::SetPageScaleFactorAndLimits(float page_scale_factor,
   SetNeedsCommit();
 }
 
+void LayerTree::SetSubframePageScaleFactor(float subframe_page_scale_factor) {
+  if (inputs_.subframe_page_scale_factor == subframe_page_scale_factor)
+    return;
+
+  inputs_.subframe_page_scale_factor = subframe_page_scale_factor;
+  SetNeedsDisplayOnAllLayers();
+}
+
 void LayerTree::StartPageScaleAnimation(const gfx::Vector2d& target_offset,
                                         bool use_anchor,
                                         float scale,
@@ -379,9 +388,9 @@ void LayerTree::PushPropertiesTo(LayerTreeImpl* tree_impl) {
   // Setting property trees must happen before pushing the page scale.
   tree_impl->SetPropertyTrees(&property_trees_);
 
-  tree_impl->PushPageScaleFromMainThread(inputs_.page_scale_factor,
-                                         inputs_.min_page_scale_factor,
-                                         inputs_.max_page_scale_factor);
+  tree_impl->PushPageScaleFromMainThread(
+      inputs_.page_scale_factor, inputs_.subframe_page_scale_factor,
+      inputs_.min_page_scale_factor, inputs_.max_page_scale_factor);
 
   tree_impl->set_browser_controls_shrink_blink_size(
       inputs_.browser_controls_shrink_blink_size);