Make PageScaleFactor work for oopif subframes.

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 e6484ec89fb90556b4f7da7ece1b7629699b6e98..b5fa3b944b9db05a99145a02f86debe2ab7ae4a7 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -56,6 +56,7 @@ namespace cc {
 LayerTreeImpl::LayerTreeImpl(
     LayerTreeHostImpl* layer_tree_host_impl,
     scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
+    scoped_refptr<SyncedProperty<ScaleGroup>> subframe_page_scale_factor,
     scoped_refptr<SyncedBrowserControls> top_controls_shown_ratio,
     scoped_refptr<SyncedElasticOverscroll> elastic_overscroll)
     : layer_tree_host_impl_(layer_tree_host_impl),
@@ -71,6 +72,7 @@ LayerTreeImpl::LayerTreeImpl(
       inner_viewport_scroll_layer_id_(Layer::INVALID_ID),
       outer_viewport_scroll_layer_id_(Layer::INVALID_ID),
       page_scale_factor_(page_scale_factor),
+      subframe_page_scale_factor_(subframe_page_scale_factor),
       min_page_scale_factor_(0),
       max_page_scale_factor_(0),
       device_scale_factor_(1.f),
@@ -451,8 +453,8 @@ void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
 
   // Active tree already shares the page_scale_factor object with pending
   // tree so only the limits need to be provided.
-  target_tree->PushPageScaleFactorAndLimits(nullptr, min_page_scale_factor(),
-                                            max_page_scale_factor());
+  target_tree->PushPageScaleFactorAndLimits(
+      nullptr, nullptr, min_page_scale_factor(), max_page_scale_factor());
   target_tree->SetDeviceScaleFactor(device_scale_factor());
   target_tree->set_painted_device_scale_factor(painted_device_scale_factor());
   target_tree->SetDeviceColorSpace(device_color_space_);
@@ -743,18 +745,39 @@ void LayerTreeImpl::SetPageScaleOnActiveTree(float active_page_scale) {
   }
 }
 
+void LayerTreeImpl::SetSubframePageScaleOnActiveTree(
+    float active_subframe_page_scale) {
+  DCHECK(IsActiveTree());
+  if (subframe_page_scale_factor()->SetCurrent(
+          ClampPageScaleFactorToLimits(active_subframe_page_scale))) {
+    DidUpdatePageScale();
+  }
+}
+
 void LayerTreeImpl::PushPageScaleFromMainThread(float page_scale_factor,
                                                 float min_page_scale_factor,
                                                 float max_page_scale_factor) {
-  PushPageScaleFactorAndLimits(&page_scale_factor, min_page_scale_factor,
-                               max_page_scale_factor);
+  PushPageScaleFactorAndLimits(&page_scale_factor, nullptr,
+                               min_page_scale_factor, max_page_scale_factor);
 }
 
-void LayerTreeImpl::PushPageScaleFactorAndLimits(const float* page_scale_factor,
-                                                 float min_page_scale_factor,
-                                                 float max_page_scale_factor) {
-  DCHECK(page_scale_factor || IsActiveTree());
+void LayerTreeImpl::PushPageScaleFromMainThread(
+    float page_scale_factor,
+    float subframe_page_scale_factor,
+    float min_page_scale_factor,
+    float max_page_scale_factor) {
+  PushPageScaleFactorAndLimits(&page_scale_factor, &subframe_page_scale_factor,
+                               min_page_scale_factor, max_page_scale_factor);
+}
+
+void LayerTreeImpl::PushPageScaleFactorAndLimits(
+    const float* page_scale_factor,
+    const float* subframe_page_scale_factor,
+    float min_page_scale_factor,
+    float max_page_scale_factor) {
+  DCHECK(page_scale_factor || subframe_page_scale_factor || IsActiveTree());
   bool changed_page_scale = false;
+  bool changed_subframe_page_scale = false;
 
   changed_page_scale |=
       SetPageScaleFactorLimits(min_page_scale_factor, max_page_scale_factor);
@@ -769,15 +792,26 @@ void LayerTreeImpl::PushPageScaleFactorAndLimits(const float* page_scale_factor,
         page_scale_factor_->PushFromMainThread(*page_scale_factor);
   }
 
+  if (subframe_page_scale_factor) {
+    changed_subframe_page_scale |= subframe_page_scale_factor_->Delta() != 1.f;
+    changed_subframe_page_scale |=
+        subframe_page_scale_factor_->PushFromMainThread(
+            *subframe_page_scale_factor);
+  }
+
   if (IsActiveTree()) {
     // TODO(enne): Pushing from pending to active should never require
     // DidUpdatePageScale.  The values should already be set by the fully
     // computed property trees being synced from one tree to another.  Remove
     // this once CDP goes away.
     changed_page_scale |= page_scale_factor_->PushPendingToActive();
+    // TODO(wjmaclean): subframe_page_scale_factor is not involved in CDP so far
+    // as I know, not sure that that means for this next line.
+    changed_subframe_page_scale |=
+        subframe_page_scale_factor_->PushPendingToActive();
   }
 
-  if (changed_page_scale)
+  if (changed_page_scale || changed_subframe_page_scale)
     DidUpdatePageScale();
 
   if (page_scale_factor) {
@@ -864,9 +898,12 @@ bool LayerTreeImpl::SetPageScaleFactorLimits(float min_page_scale_factor,
 }
 
 void LayerTreeImpl::DidUpdatePageScale() {
-  if (IsActiveTree())
+  if (IsActiveTree()) {
     page_scale_factor()->SetCurrent(
         ClampPageScaleFactorToLimits(current_page_scale_factor()));
+    subframe_page_scale_factor()->SetCurrent(
+        ClampPageScaleFactorToLimits(GetSubframePageScaleFactor()));
+  }
 
   set_needs_update_draw_properties();
   DidUpdateScrollState(inner_viewport_scroll_layer_id_);
@@ -898,6 +935,15 @@ const SyncedProperty<ScaleGroup>* LayerTreeImpl::page_scale_factor() const {
   return page_scale_factor_.get();
 }
 
+SyncedProperty<ScaleGroup>* LayerTreeImpl::subframe_page_scale_factor() {
+  return subframe_page_scale_factor_.get();
+}
+
+const SyncedProperty<ScaleGroup>* LayerTreeImpl::subframe_page_scale_factor()
+    const {
+  return subframe_page_scale_factor_.get();
+}
+
 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
   if (!InnerViewportContainerLayer())
     return gfx::SizeF();
@@ -921,6 +967,7 @@ void LayerTreeImpl::ApplySentScrollAndScaleDeltasFromAbortedCommit() {
   DCHECK(IsActiveTree());
 
   page_scale_factor()->AbortCommit();
+  subframe_page_scale_factor()->AbortCommit();
   top_controls_shown_ratio()->AbortCommit();
   elastic_overscroll()->AbortCommit();