Move page scale animation from LayerTreeHostImpl to LayerTreeImpl

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index ab6309b991003081f0d8d45eb5addade425fa620..dd000d6b750f92769bd755b287158562f30e92d7 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -432,48 +432,6 @@ void LayerTreeHostImpl::ManageTiles() {
   client_->DidManageTiles();
 }
 
-void LayerTreeHostImpl::StartPageScaleAnimation(
-    const gfx::Vector2d& target_offset,
-    bool anchor_point,
-    float page_scale,
-    base::TimeDelta duration) {
-  if (!InnerViewportScrollLayer())
-    return;
-
-  gfx::ScrollOffset scroll_total = active_tree_->TotalScrollOffset();
-  gfx::SizeF scaled_scrollable_size = active_tree_->ScrollableSize();
-  gfx::SizeF viewport_size =
-      active_tree_->InnerViewportContainerLayer()->bounds();
-
-  // Easing constants experimentally determined.
-  scoped_ptr<TimingFunction> timing_function =
-      CubicBezierTimingFunction::Create(.8, 0, .3, .9);
-
-  // TODO(miletus) : Pass in ScrollOffset.
-  page_scale_animation_ =
-      PageScaleAnimation::Create(ScrollOffsetToVector2dF(scroll_total),
-                                 active_tree_->total_page_scale_factor(),
-                                 viewport_size,
-                                 scaled_scrollable_size,
-                                 timing_function.Pass());
-
-  if (anchor_point) {
-    gfx::Vector2dF anchor(target_offset);
-    page_scale_animation_->ZoomWithAnchor(anchor,
-                                          page_scale,
-                                          duration.InSecondsF());
-  } else {
-    gfx::Vector2dF scaled_target_offset = target_offset;
-    page_scale_animation_->ZoomTo(scaled_target_offset,
-                                  page_scale,
-                                  duration.InSecondsF());
-  }
-
-  SetNeedsAnimate();
-  client_->SetNeedsCommitOnImplThread();
-  client_->RenewTreePriority();
-}
-
 bool LayerTreeHostImpl::IsCurrentlyScrollingLayerAt(
     const gfx::Point& viewport_point,
     InputHandler::ScrollInputType type) {
@@ -1855,6 +1813,13 @@ void LayerTreeHostImpl::ActivateSyncTree() {
 
   if (time_source_client_adapter_ && time_source_client_adapter_->Active())
     DCHECK(active_tree_->root_layer());
+
+  page_scale_animation_ = active_tree_->TakePageScaleAnimation();
+  if (page_scale_animation_) {
+    SetNeedsAnimate();
+    client_->SetNeedsCommitOnImplThread();
+    client_->RenewTreePriority();
+  }
 }
 
 void LayerTreeHostImpl::SetVisible(bool visible) {