Made top controls work with virtual viewport pinch-to-zoom. (Chromium)

cc/layers/layer_impl.cc

 // Copyright 2012 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/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_argument.h"
 #include "base/json/json_reader.h"
 #include "base/strings/stringprintf.h"
@@ skipping 1151 matching lines @@
 
 gfx::ScrollOffset LayerImpl::MaxScrollOffset() const {
   if (!scroll_clip_layer_ || bounds().IsEmpty())
     return gfx::ScrollOffset();
 
   LayerImpl const* page_scale_layer = layer_tree_impl()->page_scale_layer();
   DCHECK(this != page_scale_layer);
   DCHECK(this != layer_tree_impl()->InnerViewportScrollLayer() ||
          IsContainerForFixedPositionLayers());
 
-  gfx::SizeF scaled_scroll_bounds(bounds());
+  // Don't use LayerImpl::bounds() since it snaps to integral values. We'll
+  // snap post-scaling.
+  gfx::SizeF scaled_scroll_bounds(bounds_.width() + bounds_delta_.x(),
+                                  bounds_.height() + bounds_delta_.y());
 
   float scale_factor = 1.f;
   for (LayerImpl const* current_layer = this;
        current_layer != scroll_clip_layer_;
        current_layer = current_layer->parent()) {
     DCHECK(current_layer);
     float current_layer_scale = 1.f;
 
     const gfx::Transform& layer_transform = current_layer->transform();
     if (current_layer == page_scale_layer) {
@@ skipping 372 matching lines @@
 }
 
 void LayerImpl::NotifyAnimationFinished(
     base::TimeTicks monotonic_time,
     Animation::TargetProperty target_property) {
   if (target_property == Animation::ScrollOffset)
     layer_tree_impl_->InputScrollAnimationFinished();
 }
 
 }  // namespace cc