cc: Unify context losing machinery

cc/prioritized_resource_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/prioritized_resource_manager.h"
 
 #include "base/debug/trace_event.h"
 #include "base/stl_util.h"
 #include "cc/prioritized_resource.h"
 #include "cc/priority_calculator.h"
@@ skipping 294 matching lines @@
         evictBackingsToReduceMemory(memoryUseBytes() - (wastedMemory - tenPercentOfMemory),
                                     PriorityCalculator::allowEverythingCutoff(),
                                     EvictOnlyRecyclable,
                                     UnlinkBackings,
                                     resourceProvider);
 }
 
 void PrioritizedResourceManager::clearAllMemory(ResourceProvider* resourceProvider)
 {
     DCHECK(m_proxy->isImplThread() && m_proxy->isMainThreadBlocked());
-    DCHECK(resourceProvider);
     evictBackingsToReduceMemory(0,
                                 PriorityCalculator::allowEverythingCutoff(),
                                 EvictAnything,
                                 DoNotUnlinkBackings,
                                 resourceProvider);
 }
 
 bool PrioritizedResourceManager::reduceMemoryOnImplThread(size_t limitBytes, int priorityCutoff, ResourceProvider* resourceProvider)
 {
     DCHECK(m_proxy->isImplThread());
@@ skipping 71 matching lines @@
     DCHECK(resourceProvider);
     ResourceProvider::ResourceId resourceId = resourceProvider->createManagedResource(size, format, ResourceProvider::TextureUsageAny);
     PrioritizedResource::Backing* backing = new PrioritizedResource::Backing(resourceId, resourceProvider, size, format);
     m_memoryUseBytes += backing->bytes();
     return backing;
 }
 
 void PrioritizedResourceManager::evictFirstBackingResource(ResourceProvider* resourceProvider)
 {
     DCHECK(m_proxy->isImplThread());
-    DCHECK(resourceProvider);
     DCHECK(!m_backings.empty());
     PrioritizedResource::Backing* backing = m_backings.front();
 
     // Note that we create a backing and its resource at the same time, but we
     // delete the backing structure and its resource in two steps. This is because
     // we can delete the resource while the main thread is running, but we cannot
     // unlink backings while the main thread is running.
     backing->deleteResource(resourceProvider);
     m_memoryUseBytes -= backing->bytes();
     m_backings.pop_front();
@@ skipping 52 matching lines @@
     }
 #endif
 }
 
 const Proxy* PrioritizedResourceManager::proxyForDebug() const
 {
     return m_proxy;
 }
 
 }  // namespace cc