Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

cc/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/layer_tree_impl.h"
 
 #include "cc/layer_tree_host_common.h"
 #include "cc/layer_tree_host_impl.h"
+#include "cc/pinch_zoom_scrollbars_manager.h"
 
 namespace cc {
 
 LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
     : layer_tree_host_impl_(layer_tree_host_impl)
     , source_frame_number_(-1)
     , hud_layer_(0)
+    , pinch_zoom_scrollbar_vertical_(0)
+    , pinch_zoom_scrollbar_horizontal_(0)
     , root_scroll_layer_(0)
     , currently_scrolling_layer_(0)
     , scrolling_layer_id_from_previous_tree_(0) {
+  if (settings().pageScalePinchZoomEnabled)
+    pinch_zoom_scrollbars_ = PinchZoomScrollbarsManager::create();
 }
 
 LayerTreeImpl::~LayerTreeImpl() {
 }
 
 static LayerImpl* findRootScrollLayer(LayerImpl* layer)
 {
     if (!layer)
         return 0;
 
@@ skipping 18 matching lines @@
     currently_scrolling_layer_ = LayerTreeHostCommon::findLayerInSubtree(
         root_layer_.get(),
         scrolling_layer_id_from_previous_tree_);
   }
 
   scrolling_layer_id_from_previous_tree_ = 0;
 
   layer_tree_host_impl_->OnCanDrawStateChangedForTree(this);
 }
 
+void LayerTreeImpl::set_pinch_zoom_scrollbar_vertical(ScrollbarLayerImpl* layer_impl)
+{
+  pinch_zoom_scrollbar_vertical_ = layer_impl;
+  if (pinch_zoom_scrollbars_)
+    pinch_zoom_scrollbars_->setScrollbarVertical(layer_impl);
+}
+
+void LayerTreeImpl::set_pinch_zoom_scrollbar_horizontal(ScrollbarLayerImpl* layer_impl)
+{
+  pinch_zoom_scrollbar_horizontal_ = layer_impl;
+  if (pinch_zoom_scrollbars_)
+    pinch_zoom_scrollbars_->setScrollbarHorizontal(layer_impl);
+}
+
 scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
   // Clear all data structures that have direct references to the layer tree.
   scrolling_layer_id_from_previous_tree_ =
     currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
   currently_scrolling_layer_ = NULL;
 
   return root_layer_.Pass();
 }
 
 void LayerTreeImpl::ClearCurrentlyScrollingLayer() {
@@ skipping 48 matching lines @@
 std::string LayerTreeImpl::layer_tree_as_text() const {
   return layer_tree_host_impl_->layerTreeAsText();
 }
 
 DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
   return layer_tree_host_impl_->debugRectHistory();
 }
 
 
 } // namespace cc