cc: Use BeginFrameArgs

cc/trees/layer_tree_impl.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/debug/traced_value.h"
@@ skipping 93 matching lines @@
 }
 
 void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
   // The request queue should have been processed and does not require a push.
   DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
 
   target_tree->SetLatencyInfo(latency_info_);
   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().
   target_tree->set_source_frame_number(source_frame_number());
   target_tree->set_background_color(background_color());
   target_tree->set_has_transparent_background(has_transparent_background());
 
   if (ContentsTexturesPurged())
     target_tree->SetContentsTexturesPurged();
   else
@@ skipping 56 matching lines @@
 void LayerTreeImpl::SetPageScaleDelta(float delta) {
   // Clamp to the current min/max limits.
   float total = page_scale_factor_ * delta;
   if (min_page_scale_factor_ && total < min_page_scale_factor_)
     delta = min_page_scale_factor_ / page_scale_factor_;
   else if (max_page_scale_factor_ && total > max_page_scale_factor_)
     delta = max_page_scale_factor_ / page_scale_factor_;
 
   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();
 }
 
 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
   return gfx::ScaleSize(layer_tree_host_impl_->VisibleViewportSize(),
                         1.0f / total_page_scale_factor());
 }
 
 void LayerTreeImpl::UpdateMaxScrollOffset() {
@@ skipping 416 matching lines @@
 const std::vector<LayerImpl*> LayerTreeImpl::LayersWithCopyOutputRequest()
     const {
   // Only the active tree needs to know about layers with copy requests, as
   // they are aborted if not serviced during draw.
   DCHECK(IsActiveTree());
 
   return layers_with_copy_output_request_;
 }
 
 }  // namespace cc