cc: Add some debugging info to failing DCHECK in PictureLayerTilingSet

cc/resources/picture_layer_tiling_set.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_set.h"
 
 #include <limits>
 #include <set>
 #include <vector>
 
@@ skipping 98 matching lines @@
   for (PictureLayerTiling* tiling : tilings_) {
     DCHECK(tiling->tile_size() ==
            client_->CalculateTileSize(tiling->tiling_size()))
         << "tile_size: " << tiling->tile_size().ToString()
         << " tiling_size: " << tiling->tiling_size().ToString()
         << " CalculateTileSize: "
         << client_->CalculateTileSize(tiling->tiling_size()).ToString();
   }
 
   if (!tilings_.empty()) {
-    size_t num_high_res = std::count_if(tilings_.begin(), tilings_.end(),

[vmpstr, 2015/02/05 18:35:08]

heh, oh yeah we have NumHighResTilings

[danakj, 2015/02/05 18:35:52]

i didnt even know/remember that :)

-                                        [](PictureLayerTiling* tiling) {
-      return tiling->resolution() == HIGH_RESOLUTION;
-    });
-    DCHECK_LE(num_high_res, 1u);
+    DCHECK_LE(NumHighResTilings(), 1);
     // When commiting from the main thread the high res tiling may get dropped,
     // but when cloning to the active tree, there should always be one.
-    if (twin_set)
-      DCHECK_EQ(1u, num_high_res);
+    if (twin_set) {
+      DCHECK_EQ(1, NumHighResTilings())
+          << " num tilings on active: " << tilings_.size()
+          << " num tilings on pending: " << twin_set->tilings_.size()
+          << " num high res on pending: " << twin_set->NumHighResTilings()
+          << " are on active tree: " << (client_->GetTree() == ACTIVE_TREE);
+    }
   }
 #endif
 }
 
 void PictureLayerTilingSet::CleanUpTilings(
     float min_acceptable_high_res_scale,
     float max_acceptable_high_res_scale,
     const std::vector<PictureLayerTiling*>& needed_tilings,
     bool should_have_low_res,
     PictureLayerTilingSet* twin_set,
@@ skipping 69 matching lines @@
       contents_scale, raster_source, client_, max_tiles_for_interest_area_,
       skewport_target_time_in_seconds_,
       skewport_extrapolation_limit_in_content_pixels_));
   PictureLayerTiling* appended = tilings_.back();
 
   tilings_.sort(LargestToSmallestScaleFunctor());
   return appended;
 }
 
 int PictureLayerTilingSet::NumHighResTilings() const {
-  int num_high_res = 0;
-  for (size_t i = 0; i < tilings_.size(); ++i) {
-    if (tilings_[i]->resolution() == HIGH_RESOLUTION)
-      num_high_res++;
-  }
-  return num_high_res;
+  return std::count_if(tilings_.begin(), tilings_.end(),
+                       [](PictureLayerTiling* tiling) {
+    return tiling->resolution() == HIGH_RESOLUTION;
+  });
 }
 
 PictureLayerTiling* PictureLayerTilingSet::FindTilingWithScale(
     float scale) const {
   for (size_t i = 0; i < tilings_.size(); ++i) {
     if (tilings_[i]->contents_scale() == scale)
       return tilings_[i];
   }
   return NULL;
 }
@@ skipping 303 matching lines @@
     case LOWER_THAN_LOW_RES:
       range = TilingRange(low_res_range.end, tilings_.size());
       break;
   }
 
   DCHECK_LE(range.start, range.end);
   return range;
 }
 
 }  // namespace cc