cc: Make tiles that are not required by trees NEVER_BIN

cc/resources/tile_manager.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/tile_manager.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/traced_value.h"
 #include "cc/resources/image_raster_worker_pool.h"
 #include "cc/resources/pixel_buffer_raster_worker_pool.h"
 #include "cc/resources/tile.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/gfx/rect_conversions.h"
 
 namespace cc {
 
 namespace {
 
 // Determine bin based on three categories of tiles: things we need now,
 // things we need soon, and eventually.
 inline TileManagerBin BinFromTilePriority(const TilePriority& prio,
                                           TreePriority tree_priority) {
+  if (!prio.required_by_tree)

[reveman, 2013/06/21 01:59:16]

is there a case where this is different than "distance_to_visible_in_pixels ==
std::numeric_limits<float>::infinity()"? I'd prefer to use that if possible but
I'm OK with this too.

nit: move this check below the constants. I don't see a reason for this to be
different than the other if statements.

+    return NEVER_BIN;
+
   // The amount of time for which we want to have prepainting coverage.
   const float kPrepaintingWindowTimeSeconds = 1.0f;
   const float kBackflingGuardDistancePixels = 314.0f;
 
   // Don't let low res tiles be in the now bin unless we're in a mode where
   // we're prioritizing checkerboard prevention.
   bool can_be_in_now_bin = tree_priority == SMOOTHNESS_TAKES_PRIORITY ||
                            prio.resolution != LOW_RESOLUTION;
 
   if (can_be_in_now_bin && prio.time_to_visible_in_seconds == 0)
@@ skipping 760 matching lines @@
 }
 
 void TileManager::DidTileTreeBinChange(Tile* tile,
                                        TileManagerBin new_tree_bin,
                                        WhichTree tree) {
   ManagedTileState& mts = tile->managed_state();
   mts.tree_bin[tree] = new_tree_bin;
 }
 
 }  // namespace cc