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

cc/tree_synchronizer.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/tree_synchronizer.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "cc/layer.h"
 #include "cc/layer_impl.h"
@@ skipping 73 matching lines @@
     layerImpl->clearChildList();
     for (size_t i = 0; i < layer->children().size(); ++i)
         layerImpl->addChild(synchronizeTreesRecursiveInternal(newLayers, oldLayers, layer->childAt(i), treeImpl));
 
     layerImpl->setMaskLayer(synchronizeTreesRecursiveInternal(newLayers, oldLayers, layer->maskLayer(), treeImpl));
     layerImpl->setReplicaLayer(synchronizeTreesRecursiveInternal(newLayers, oldLayers, layer->replicaLayer(), treeImpl));
 
     // Remove all dangling pointers. The pointers will be setup later in updateScrollbarLayerPointersRecursive phase
     layerImpl->setHorizontalScrollbarLayer(0);
     layerImpl->setVerticalScrollbarLayer(0);
+    layerImpl->setHorizontalPinchZoomScrollbarLayer(0);
+    layerImpl->setVerticalPinchZoomScrollbarLayer(0);
 
     return layerImpl.Pass();
 }
 
 scoped_ptr<LayerImpl> synchronizeTreesRecursive(RawPtrLayerImplMap& newLayers, ScopedPtrLayerImplMap& oldLayers, Layer* layer, LayerTreeImpl* treeImpl)
 {
     return synchronizeTreesRecursiveInternal(newLayers, oldLayers, layer, treeImpl);
 }
 
 scoped_ptr<LayerImpl> synchronizeTreesRecursive(RawPtrLayerImplMap& newLayers, ScopedPtrLayerImplMap& oldLayers, LayerImpl* layer, LayerTreeImpl* treeImpl)
@@ skipping 15 matching lines @@
         return;
 
     RawPtrLayerImplMap::const_iterator iter = newLayers.find(scrollbarLayer->id());
     ScrollbarLayerImpl* scrollbarLayerImpl = iter != newLayers.end() ? static_cast<ScrollbarLayerImpl*>(iter->second) : NULL;
     iter = newLayers.find(scrollbarLayer->scrollLayerId());
     LayerImpl* scrollLayerImpl = iter != newLayers.end() ? iter->second : NULL;
 
     DCHECK(scrollbarLayerImpl);
     DCHECK(scrollLayerImpl);
 
-    if (scrollbarLayer->orientation() == WebKit::WebScrollbar::Horizontal)
-        scrollLayerImpl->setHorizontalScrollbarLayer(scrollbarLayerImpl);
-    else
-        scrollLayerImpl->setVerticalScrollbarLayer(scrollbarLayerImpl);
+    if (scrollbarLayer->isPinchZoomScrollbar()) {
+        if (scrollbarLayer->orientation() == WebKit::WebScrollbar::Horizontal)
+            scrollLayerImpl->setHorizontalPinchZoomScrollbarLayer(scrollbarLayerImpl);
+        else
+            scrollLayerImpl->setVerticalPinchZoomScrollbarLayer(scrollbarLayerImpl);
+    } else {
+        if (scrollbarLayer->orientation() == WebKit::WebScrollbar::Horizontal)
+            scrollLayerImpl->setHorizontalScrollbarLayer(scrollbarLayerImpl);
+        else
+            scrollLayerImpl->setVerticalScrollbarLayer(scrollbarLayerImpl);
+    }
 }
 
 void updateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap& newLayers, Layer* layer)
 {
     updateScrollbarLayerPointersRecursiveInternal<Layer, ScrollbarLayer>(newLayers, layer);
 }
 
 void updateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap& newLayers, LayerImpl* layer)
 {
     updateScrollbarLayerPointersRecursiveInternal<LayerImpl, ScrollbarLayerImpl>(newLayers, layer);
@@ skipping 26 matching lines @@
     pushPropertiesInternal(layer, layerImpl);
 }
 
 void TreeSynchronizer::pushProperties(LayerImpl* layer, LayerImpl* layerImpl)
 {
     pushPropertiesInternal(layer, layerImpl);
 }
 
 
 }  // namespace cc