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

cc/animation/layer_animation_controller.cc

 // Copyright 2012 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/animation/layer_animation_controller.h"
 
 #include <algorithm>
+#include <vector>
 
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_delegate.h"
 #include "cc/animation/animation_registrar.h"
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/layer_animation_value_observer.h"
 #include "cc/animation/layer_animation_value_provider.h"
 #include "cc/animation/scroll_offset_animation_curve.h"
 #include "cc/base/scoped_ptr_algorithm.h"
 #include "cc/output/filter_operations.h"
@@ skipping 469 matching lines @@
 
     const TransformAnimationCurve* transform_animation_curve =
         animations_[i]->curve()->ToTransformAnimationCurve();
     if (!transform_animation_curve->IsTranslation())
       return false;
   }
 
   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() ||
         animations_[i]->target_property() != Animation::Transform)
       continue;
 
+    bool forward_direction = true;
+    switch (animations_[i]->direction()) {
+      case Animation::Normal:
+      case Animation::Alternate:
+        forward_direction = animations_[i]->playback_rate() >= 0.0;
+        break;
+      case Animation::Reverse:
+      case Animation::AlternateReverse:
+        forward_direction = animations_[i]->playback_rate() < 0.0;
+        break;
+    }
+
     const TransformAnimationCurve* transform_animation_curve =
         animations_[i]->curve()->ToTransformAnimationCurve();
     float animation_scale = 0.f;
-    if (!transform_animation_curve->MaximumScale(&animation_scale))
+    if (!transform_animation_curve->MaximumTargetScale(forward_direction,
+                                                       &animation_scale))
       return false;
     *max_scale = std::max(*max_scale, animation_scale);
   }
 
   return true;
 }
 
 void LayerAnimationController::PushNewAnimationsToImplThread(
     LayerAnimationController* controller_impl) const {
   // Any new animations owned by the main thread's controller are cloned and
@@ skipping 496 matching lines @@
         value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr)
       if (obs->IsActive())
         return true;
   }
   return false;
 }
 
 }  // namespace cc