cc: Make PictureLayerImpl use a better choice for animated raster scale.

cc/animation/layer_animation_controller.cc

Index: cc/animation/layer_animation_controller.cc
diff --git a/cc/animation/layer_animation_controller.cc b/cc/animation/layer_animation_controller.cc
index 911c5c426f57814305e2d69fb7ddf352290480bd..fad178e79aec8054bab54fd7d9e64890b1b308ac 100644
--- a/cc/animation/layer_animation_controller.cc
+++ b/cc/animation/layer_animation_controller.cc
@@ -5,6 +5,7 @@
 #include "cc/animation/layer_animation_controller.h"
 
 #include <algorithm>
+#include <vector>
 
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_delegate.h"
@@ -494,7 +495,7 @@ bool LayerAnimationController::HasOnlyTranslationTransforms() const {
   return true;
 }
 
-bool LayerAnimationController::MaximumScale(float* max_scale) const {
+bool LayerAnimationController::MaximumTargetScale(float* max_scale) const {
   *max_scale = 0.f;
   for (size_t i = 0; i < animations_.size(); ++i) {
     if (animations_[i]->is_finished() ||
@@ -504,7 +505,7 @@ bool LayerAnimationController::MaximumScale(float* max_scale) const {
     const TransformAnimationCurve* transform_animation_curve =
         animations_[i]->curve()->ToTransformAnimationCurve();

[ajuma, 2014/10/10 13:43:07]

We also need to account for animations being run in reverse (which would be
those with Reverse or AlternateReverse direction and positive playback rate, and
those with Normal or Alternate direction and negative playback rate), since that
changes the targets to consider (the endpoint of the last keyframe is the real
starting point).

[danakj, 2014/10/10 15:14:45]

OK I think I have this now, thanks!

     float animation_scale = 0.f;
-    if (!transform_animation_curve->MaximumScale(&animation_scale))
+    if (!transform_animation_curve->MaximumTargetScale(&animation_scale))
       return false;
     *max_scale = std::max(*max_scale, animation_scale);
   }