cc: Fix RasterWorkerPool shutdown crash.

cc/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/tile_manager.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 108 matching lines @@
     TileManagerClient* client,
     ResourceProvider* resource_provider,
     size_t num_raster_threads)
     : client_(client),
       resource_pool_(ResourcePool::Create(resource_provider)),
       raster_worker_pool_(RasterWorkerPool::Create(num_raster_threads)),
       manage_tiles_pending_(false),
       manage_tiles_call_count_(0),
       bytes_pending_set_pixels_(0),
       ever_exceeded_memory_budget_(false) {
+  bool worker_pool_is_running = raster_worker_pool_->Start();
+  CHECK(worker_pool_is_running);
+
   for (int i = 0; i < NUM_STATES; ++i) {
     for (int j = 0; j < NUM_TREES; ++j) {
       for (int k = 0; k < NUM_BINS; ++k)
         raster_state_count_[i][j][k] = 0;
     }
   }
 }
 
 TileManager::~TileManager() {
   // Reset global state and manage. This should cause
@@ skipping 608 matching lines @@
   --raster_state_count_[mts.raster_state][tree][mts.tree_bin[tree]];
   DCHECK_GE(raster_state_count_[mts.raster_state][tree][mts.tree_bin[tree]], 0);
 
   // Increment count for new bin.
   ++raster_state_count_[mts.raster_state][tree][bin];
 
   mts.tree_bin[tree] = bin;
 }
 
 }  // namespace cc