cc: Simplify picture layer tiling update tile priorities.

cc/resources/prioritized_tile_set.cc

 // Copyright 2013 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/prioritized_tile_set.h"
 
 #include <algorithm>
 
 #include "cc/resources/managed_tile_state.h"
 #include "cc/resources/tile.h"
 
 namespace cc {
 
 class BinComparator {
  public:
   bool operator()(const Tile* a,
                   const Tile* b) const {
     const ManagedTileState& ams = a->managed_state();
     const ManagedTileState& bms = b->managed_state();
 
+    if (ams.priority_bin != bms.priority_bin)

[enne (OOO), 2014/01/31 23:07:46]

Isn't the bin comparator for tiles in the same bin? Shouldn't it always be the
case that the bins are the same?

[vmpstr, 2014/02/03 20:27:24]

Not exactly. I mean, I hope that in the near future the priority bins stuff
(NOW_BIN/SOON_BIN/EVENTUALLY_BIN/AT_LAST_BIN/NEVER_BIN/and all active versions
as well) will go away. Until that time, it just happens that TilePriority::NOW
maps to NOW_BIN, but it doesn't have to be that way. The prioritized tile set
splits into bins as in ManagedTileBin, not as in TilePriority::PriorityBin.

It's somewhat confusing to have two different types that represent bins, but
ManagedTileBin has a few more bins based on tree priority and whether the tile
is currently being rasterized. I would prefer to keep it that way for now. Wdyt?

+      return ams.priority_bin < bms.priority_bin;
+
     if (ams.required_for_activation != bms.required_for_activation)
       return ams.required_for_activation;
 
     if (ams.resolution != bms.resolution)
       return ams.resolution < bms.resolution;
 
-    if (ams.time_to_needed_in_seconds !=  bms.time_to_needed_in_seconds)
-      return ams.time_to_needed_in_seconds < bms.time_to_needed_in_seconds;
-
-    if (ams.distance_to_visible_in_pixels !=
-        bms.distance_to_visible_in_pixels) {
-      return ams.distance_to_visible_in_pixels <
-             bms.distance_to_visible_in_pixels;
-    }
+    if (ams.distance_to_visible != bms.distance_to_visible)
+      return ams.distance_to_visible < bms.distance_to_visible;
 
     gfx::Rect a_rect = a->content_rect();
     gfx::Rect b_rect = b->content_rect();
     if (a_rect.y() != b_rect.y())
       return a_rect.y() < b_rect.y();
     return a_rect.x() < b_rect.x();
   }
 };
 
 namespace {
@@ skipping 89 matching lines @@
     if (use_priority_ordering_)
       tile_set_->SortBinIfNeeded(current_bin_);
 
     iterator_ = tile_set_->tiles_[current_bin_].begin();
     if (iterator_ != tile_set_->tiles_[current_bin_].end())
       break;
   }
 }
 
 }  // namespace cc