cc: Compute animation scale on demand

cc/trees/property_tree_builder.cc

 // Copyright 2014 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/trees/property_tree_builder.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <set>
@@ skipping 540 matching lines @@
       node->id, data_for_children->property_trees->effect_tree
                     .Node(data_for_children->render_target)
                     ->data.transform_id);
   DCHECK_NE(
       data_for_children->property_trees->transform_tree.TargetId(node->id),
       kInvalidPropertyTreeNodeId);
 
   node->data.has_potential_animation = has_potentially_animated_transform;
   node->data.is_currently_animating = layer->TransformIsAnimating();
   if (has_potentially_animated_transform) {
-    float maximum_animation_target_scale = 0.f;
-    if (layer->MaximumTargetScale(&maximum_animation_target_scale)) {
-      node->data.local_maximum_animation_target_scale =
-          maximum_animation_target_scale;
-    }
-
-    float starting_animation_scale = 0.f;
-    if (layer->AnimationStartScale(&starting_animation_scale)) {
-      node->data.local_starting_animation_scale = starting_animation_scale;
-    }
-
     node->data.has_only_translation_animations =
         layer->HasOnlyTranslationTransforms();
   }
 
   float post_local_scale_factor = 1.0f;
   if (is_root)
     post_local_scale_factor =
         data_for_children->property_trees->transform_tree.device_scale_factor();
 
   if (is_page_scale_layer) {
@@ skipping 804 matching lines @@
   property_trees->is_main_thread = false;
   property_trees->is_active = root_layer->IsActive();
   SkColor color = root_layer->layer_tree_impl()->background_color();
   if (SkColorGetA(color) != 255)
     color = SkColorSetA(color, 255);
   BuildPropertyTreesTopLevelInternal(
       root_layer, page_scale_layer, inner_viewport_scroll_layer,
       outer_viewport_scroll_layer, overscroll_elasticity_layer,
       elastic_overscroll, page_scale_factor, device_scale_factor, viewport,
       device_transform, property_trees, color);
+  property_trees->ResetCachedData();

[jaydasika, 2016/06/28 23:08:40]

Should this also be in the Layer version of the function ? Or maybe, put it
inside BuildPropertyTreesTopLevelInternal so that all clearing code is in one
place ?

[sunxd, 2016/06/30 15:29:44]

The only place where animation scales get used is in PictureLayerImpl in
production code, and ResetCachedData is called when pushing property trees from
main to impl. This line here is only for testing. Maybe when we decide to move
other stuff from property trees to the cached data structure, we need to reset
the cache on main thread, but I would still stick to this currently.

 }
 
 }  // namespace cc