cc: Simplify the logic for deciding to update tile priorities.

cc/resources/picture_layer_tiling.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/resources/picture_layer_tiling.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/debug/trace_event.h"
@@ skipping 13 matching lines @@
 scoped_ptr<PictureLayerTiling> PictureLayerTiling::Clone() const {
   return make_scoped_ptr(new PictureLayerTiling(*this));
 }
 
 PictureLayerTiling::PictureLayerTiling(float contents_scale)
     : client_(NULL),
       contents_scale_(contents_scale),
       tiling_data_(gfx::Size(), gfx::Size(), true),
       resolution_(NON_IDEAL_RESOLUTION),
       last_source_frame_number_(0),
-      last_impl_frame_time_(0) {
+      last_impl_frame_time_(0.0) {
 }
 
 PictureLayerTiling::~PictureLayerTiling() {
 }
 
 void PictureLayerTiling::SetClient(PictureLayerTilingClient* client) {
   client_ = client;
 }
 
 gfx::Rect PictureLayerTiling::ContentRect() const {
@@ skipping 297 matching lines @@
     WhichTree tree,
     gfx::Size device_viewport,
     const gfx::RectF& viewport_in_layer_space,
     const gfx::RectF& visible_layer_rect,
     gfx::Size last_layer_bounds,
     gfx::Size current_layer_bounds,
     float last_layer_contents_scale,
     float current_layer_contents_scale,
     const gfx::Transform& last_screen_transform,
     const gfx::Transform& current_screen_transform,
-    int current_source_frame_number,
     double current_frame_time,
     bool store_screen_space_quads_on_tiles,
     size_t max_tiles_for_interest_area) {
   if (ContentRect().IsEmpty())
     return;
 
-  bool first_update_in_new_source_frame =
-      current_source_frame_number != last_source_frame_number_;
-
-  bool first_update_in_new_impl_frame =
-      current_frame_time != last_impl_frame_time_;
-
-  // In pending tree, this is always called. We update priorities:
-  // - Immediately after a commit (first_update_in_new_source_frame).
-  // - On animation ticks after the first frame in the tree
-  //   (first_update_in_new_impl_frame).
-  // In active tree, this is only called during draw. We update priorities:
-  // - On draw if properties were not already computed by the pending tree
-  //   and activated for the frame (first_update_in_new_impl_frame).
-  if (!first_update_in_new_impl_frame && !first_update_in_new_source_frame)
-    return;
-
   double time_delta = 0;
   if (last_impl_frame_time_ != 0 && last_layer_bounds == current_layer_bounds)
     time_delta = current_frame_time - last_impl_frame_time_;
 
   gfx::Rect viewport_in_content_space =
       gfx::ToEnclosingRect(gfx::ScaleRect(viewport_in_layer_space,
                                           contents_scale_));
   gfx::Rect visible_content_rect =
       gfx::ToEnclosingRect(gfx::ScaleRect(visible_layer_rect,
                                           contents_scale_));
@@ skipping 114 matching lines @@
           bool clipped;
           priority.set_current_screen_quad(
             MathUtil::MapQuad(current_screen_transform,
                               gfx::QuadF(current_layer_content_rect),
                               &clipped));
       }
       tile->SetPriority(tree, priority);
     }
   }
 
-  last_source_frame_number_ = current_source_frame_number;
   last_impl_frame_time_ = current_frame_time;
 }
 
 void PictureLayerTiling::DidBecomeActive() {
   for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
     it->second->SetPriority(ACTIVE_TREE, it->second->priority(PENDING_TREE));
     it->second->SetPriority(PENDING_TREE, TilePriority());
 
     // Tile holds a ref onto a picture pile. If the tile never gets invalidated
     // and recreated, then that picture pile ref could exist indefinitely.  To
@@ skipping 133 matching lines @@
 
     // If our delta is less then our event distance, we're done.
     if (delta < event.distance)
       break;
   }
 
   return gfx::Rect(origin_x, origin_y, width, height);
 }
 
 }  // namespace cc