cc: Do not save the rasterScale for layers until they are finished animating transforms.

cc/layer_tree_host_common.cc

Index: cc/layer_tree_host_common.cc
diff --git a/cc/layer_tree_host_common.cc b/cc/layer_tree_host_common.cc
index 662d5d82098e4a224d060daaa854c9b4ac3cf06b..e64a339aa8c2f3d7afc0848bdd401e50336f015c 100644
--- a/cc/layer_tree_host_common.cc
+++ b/cc/layer_tree_host_common.cc
@@ -349,15 +349,15 @@ WebTransformationMatrix computeScrollCompensationMatrixForChildren(LayerImpl* la
 }
 
 // There is no contentsScale on impl thread.
-static inline void updateLayerContentsScale(LayerImpl*, const WebTransformationMatrix&, float, float) { }
+static inline void updateLayerContentsScale(LayerImpl*, const WebTransformationMatrix&, float, float, bool) { }
 
-static inline void updateLayerContentsScale(Layer* layer, const WebTransformationMatrix& combinedTransform, float deviceScaleFactor, float pageScaleFactor)
+static inline void updateLayerContentsScale(Layer* layer, const WebTransformationMatrix& combinedTransform, float deviceScaleFactor, float pageScaleFactor, bool animatingTransformToScreen)
 {
     float rasterScale = layer->rasterScale();
     if (!rasterScale) {
         rasterScale = 1;
 
-        if (layer->automaticallyComputeRasterScale()) {
+        if (!animatingTransformToScreen && layer->automaticallyComputeRasterScale()) {
             gfx::Vector2dF transformScale = MathUtil::computeTransform2dScaleComponents(combinedTransform);
             float combinedScale = std::max(transformScale.x(), transformScale.y());
             rasterScale = combinedScale / deviceScaleFactor;
@@ -489,6 +489,13 @@ static void calculateDrawTransformsInternal(LayerType* layer, const WebTransform
         drawOpacityIsAnimating |= layer->parent()->drawOpacityIsAnimating();
     }
 
+    bool animatingTransformToTarget = layer->transformIsAnimating();
+    bool animatingTransformToScreen = animatingTransformToTarget;
+    if (layer->parent()) {
+        animatingTransformToTarget |= layer->parent()->drawTransformIsAnimating();
+        animatingTransformToScreen |= layer->parent()->screenSpaceTransformIsAnimating();
+    }
+
     gfx::Size bounds = layer->bounds();
     gfx::PointF anchorPoint = layer->anchorPoint();
     gfx::PointF position = layer->position() - layer->scrollDelta();
@@ -506,7 +513,7 @@ static void calculateDrawTransformsInternal(LayerType* layer, const WebTransform
 
     // The layer's contentsSize is determined from the combinedTransform, which then informs the
     // layer's drawTransform.
-    updateLayerContentsScale(layer, combinedTransform, deviceScaleFactor, pageScaleFactor);
+    updateLayerContentsScale(layer, combinedTransform, deviceScaleFactor, pageScaleFactor, animatingTransformToScreen);
 
     // If there is a tranformation from the impl thread then it should be at the
     // start of the combinedTransform, but we don't want it to affect the contentsScale.
@@ -535,13 +542,6 @@ static void calculateDrawTransformsInternal(LayerType* layer, const WebTransform
     layerScreenSpaceTransform.multiply(drawTransform);
     layer->setScreenSpaceTransform(layerScreenSpaceTransform);
 
-    bool animatingTransformToTarget = layer->transformIsAnimating();
-    bool animatingTransformToScreen = animatingTransformToTarget;
-    if (layer->parent()) {
-        animatingTransformToTarget |= layer->parent()->drawTransformIsAnimating();
-        animatingTransformToScreen |= layer->parent()->screenSpaceTransformIsAnimating();
-    }
-
     gfx::RectF contentRect(gfx::PointF(), layer->contentBounds());
 
     // fullHierarchyMatrix is the matrix that transforms objects between screen space (except projection matrix) and the most recent RenderSurfaceImpl's space.