Animation start scale should be considered for the 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"
@@ skipping 495 matching lines @@
 
     const TransformAnimationCurve* transform_animation_curve =
         animations_[i]->curve()->ToTransformAnimationCurve();
     if (!transform_animation_curve->PreservesAxisAlignment())
       return false;
   }
 
   return true;
 }
 
+bool LayerAnimationController::AnimationStartScale(float* start_scale) const {
+  *start_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::DIRECTION_NORMAL:
+      case Animation::DIRECTION_ALTERNATE:
+        forward_direction = animations_[i]->playback_rate() >= 0.0;
+        break;
+      case Animation::DIRECTION_REVERSE:
+      case Animation::DIRECTION_ALTERNATE_REVERSE:
+        forward_direction = animations_[i]->playback_rate() < 0.0;
+        break;
+    }
+
+    const TransformAnimationCurve* transform_animation_curve =
+        animations_[i]->curve()->ToTransformAnimationCurve();
+    float animation_start_scale = 0.f;
+    if (!transform_animation_curve->AnimationStartScale(forward_direction,
+                                                        &animation_start_scale))
+      return false;
+    *start_scale = std::max(*start_scale, animation_start_scale);
+  }
+  return true;
+}
+
 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::DIRECTION_NORMAL:
@@ skipping 512 matching lines @@
         &value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr)
       if (obs->IsActive())
         return true;
   }
   return false;
 }
 
 }  // namespace cc