Revert of Remove DCHECK_IMPLIES/CHECK_IMPLIES.

cc/tiles/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/tiles/tile_manager.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 503 matching lines @@
 
     // We won't be able to schedule this tile, so break out early.
     if (tiles_that_need_to_be_rasterized->size() >=
         scheduled_raster_task_limit) {
       all_tiles_that_need_to_be_rasterized_are_scheduled_ = false;
       break;
     }
 
     tile->scheduled_priority_ = schedule_priority++;
 
-    DCHECK(tile->draw_info().mode() == TileDrawInfo::OOM_MODE ||
-           !tile->draw_info().IsReadyToDraw());
+    DCHECK_IMPLIES(tile->draw_info().mode() != TileDrawInfo::OOM_MODE,
+                   !tile->draw_info().IsReadyToDraw());
 
     // If the tile already has a raster_task, then the memory used by it is
     // already accounted for in memory_usage. Otherwise, we'll have to acquire
     // more memory to create a raster task.
     MemoryUsage memory_required_by_tile_to_be_scheduled;
     if (!tile->raster_task_.get()) {
       memory_required_by_tile_to_be_scheduled = MemoryUsage::FromConfig(
           tile->desired_texture_size(), DetermineResourceFormat(tile));
     }
 
@@ skipping 252 matching lines @@
   for (; !raster_priority_queue->IsEmpty(); raster_priority_queue->Pop()) {
     if (!raster_priority_queue->Top().tile()->draw_info().IsReadyToDraw())
       return false;
   }
 
 #if DCHECK_IS_ON()
   scoped_ptr<RasterTilePriorityQueue> all_queue(
       client_->BuildRasterQueue(global_state_.tree_priority, type));
   for (; !all_queue->IsEmpty(); all_queue->Pop()) {
     Tile* tile = all_queue->Top().tile();
-    DCHECK(!tile->required_for_activation() ||
-           tile->draw_info().IsReadyToDraw());
+    DCHECK_IMPLIES(tile->required_for_activation(),
+                   tile->draw_info().IsReadyToDraw());
   }
 #endif
   return true;
 }
 
 bool TileManager::IsReadyToActivate() const {
   TRACE_EVENT0("cc", "TileManager::IsReadyToActivate");
   return AreRequiredTilesReadyToDraw(
       RasterTilePriorityQueue::Type::REQUIRED_FOR_ACTIVATION);
 }
@@ skipping 195 matching lines @@
 void TileManager::Signals::reset() {
   ready_to_activate = false;
   did_notify_ready_to_activate = false;
   ready_to_draw = false;
   did_notify_ready_to_draw = false;
   all_tile_tasks_completed = false;
   did_notify_all_tile_tasks_completed = false;
 }
 
 }  // namespace cc