Chromium compositor change implementing page-scale driven pinch-zoom.

cc/CCLayerTreeHostCommon.cpp

 // 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 "config.h"
 
 #include "CCLayerTreeHostCommon.h"
 
 #include "CCLayerImpl.h"
@@ skipping 444 matching lines @@
     FloatPoint anchorPoint = layer->anchorPoint();
     FloatPoint position = layer->position() - layer->scrollDelta();
 
     // Offset between anchor point and the center of the quad.
     float centerOffsetX = (0.5 - anchorPoint.x()) * bounds.width();
     float centerOffsetY = (0.5 - anchorPoint.y()) * bounds.height();
 
     WebTransformationMatrix layerLocalTransform;
     // LT = S[pageScaleDelta]
     layerLocalTransform.scale(layer->pageScaleDelta());
+    layerLocalTransform.scale(layer->pageScaleFactor());
+    layerLocalTransform.translate(layer->localOffset().width(), layer->localOffset().height());
     // LT = S[pageScaleDelta] * Tr[origin] * Tr[origin2anchor]
     layerLocalTransform.translate3d(position.x() + anchorPoint.x() * bounds.width(), position.y() + anchorPoint.y() * bounds.height(), layer->anchorPointZ());
     // LT = S[pageScaleDelta] * Tr[origin] * Tr[origin2anchor] * M[layer]
     layerLocalTransform.multiply(layer->transform());
     // LT = S[pageScaleDelta] * Tr[origin] * Tr[origin2anchor] * M[layer] * Tr[anchor2center]
     layerLocalTransform.translate3d(centerOffsetX, centerOffsetY, -layer->anchorPointZ());
 
     WebTransformationMatrix combinedTransform = parentMatrix;
     combinedTransform.multiply(layerLocalTransform);
 
@@ skipping 401 matching lines @@
 
         foundLayer = currentLayer;
         break;
     }
 
     // This can potentially return 0, which means the viewportPoint did not successfully hit test any layers, not even the root layer.
     return foundLayer;
 }
 
 } // namespace WebCore