cc: Use BeginFrameArgs

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 be25e6543063f5cba9201e8d242a6e7fec4e55fc..84581f5198a7d3d9dee49495b8a8098ce541d5ef 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -111,9 +111,8 @@ void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
   latency_info_.Clear();
   target_tree->SetPageScaleFactorAndLimits(
       page_scale_factor(), min_page_scale_factor(), max_page_scale_factor());
-  target_tree->SetPageScaleDelta(
-      target_tree->page_scale_delta() / target_tree->sent_page_scale_delta());
-  target_tree->set_sent_page_scale_delta(1);
+  target_tree->SetPageScaleDelta(page_scale_delta());
+  target_tree->set_sent_page_scale_delta(sent_page_scale_delta());

[enne (OOO), 2013/08/06 23:35:16]

If you're going to change this code, can you DCHECK that sent page scale delta
here is 1?

 
   // This should match the property synchronization in
   // LayerTreeHost::finishCommitOnImplThread().
@@ -190,18 +189,8 @@ void LayerTreeImpl::SetPageScaleDelta(float delta) {
 
   if (delta == page_scale_delta_)
     return;
-
   page_scale_delta_ = delta;
 
-  if (IsActiveTree()) {
-    LayerTreeImpl* pending_tree = layer_tree_host_impl_->pending_tree();
-    if (pending_tree) {
-      DCHECK_EQ(1, pending_tree->sent_page_scale_delta());
-      pending_tree->SetPageScaleDelta(

[enne (OOO), 2013/08/06 23:35:16]

This is what keeps the pending tree's total page scale factor up to date during
a pinch gesture.

You've added it to AnimatePinchGesture, but not all pinches are animated. 
There's also this one:
https://code.google.com/p/chromium/codesearch#chromium/src/cc/trees/layer_tre...

Is there a reason to change this?

-          page_scale_delta_ / sent_page_scale_delta_);
-    }
-  }
-
   UpdateMaxScrollOffset();
   set_needs_update_draw_properties();
 }