cc: Make images that can't possibly fit in cache not checker.

cc/tiles/gpu_image_decode_cache.h

 // Copyright 2016 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.
 
 #ifndef CC_TILES_GPU_IMAGE_DECODE_CACHE_H_
 #define CC_TILES_GPU_IMAGE_DECODE_CACHE_H_
 
 #include <memory>
 #include <unordered_map>
 #include <vector>
@@ skipping 107 matching lines @@
       const DrawImage& image,
       scoped_refptr<TileTask>* task) override;
   void UnrefImage(const DrawImage& image) override;
   DecodedDrawImage GetDecodedImageForDraw(const DrawImage& draw_image) override;
   void DrawWithImageFinished(const DrawImage& image,
                              const DecodedDrawImage& decoded_image) override;
   void ReduceCacheUsage() override;
   void SetShouldAggressivelyFreeResources(
       bool aggressively_free_resources) override;
   void ClearCache() override;
+  size_t GetMaximumMemoryLimit() const override;
 
   // MemoryDumpProvider overrides.
   bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                     base::trace_event::ProcessMemoryDump* pmd) override;
 
   // base::MemoryCoordinatorClient overrides.
   void OnMemoryStateChange(base::MemoryState state) override;
   void OnPurgeMemory() override;
 
   // Called by Decode / Upload tasks.
@@ skipping 202 matching lines @@
   // The following two functions also require the |context_| lock to be held.
   void UploadImageIfNecessary(const DrawImage& draw_image,
                               ImageData* image_data);
   void DeletePendingImages();
 
   const ResourceFormat format_;
   ContextProvider* context_;
   sk_sp<GrContextThreadSafeProxy> context_threadsafe_proxy_;
 
   // All members below this point must only be accessed while holding |lock_|.
+  // The exception are const members like |normal_max_cache_bytes_| that can
+  // be accessed without a lock since they are thread safe.
   base::Lock lock_;
 
   // |persistent_cache_| represents the long-lived cache, keeping a certain
   // budget of ImageDatas alive even when their ref count reaches zero.
   using PersistentCache = base::MRUCache<uint32_t, scoped_refptr<ImageData>>;
   PersistentCache persistent_cache_;
 
   // |in_use_cache_| represents the in-use (short-lived) cache. Entries are
   // cleaned up as soon as their ref count reaches zero.
   using InUseCache =
       std::unordered_map<InUseCacheKey, InUseCacheEntry, InUseCacheKeyHash>;
   InUseCache in_use_cache_;
 
   size_t max_working_set_bytes_;
   const size_t normal_max_cache_bytes_;
   size_t cached_bytes_limit_ = normal_max_cache_bytes_;
   size_t bytes_used_ = 0;
   base::MemoryState memory_state_ = base::MemoryState::NORMAL;
 
   // We can't release GPU backed SkImages without holding the context lock,
   // so we add them to this list and defer deletion until the next time the lock
   // is held.
   std::vector<sk_sp<SkImage>> images_pending_deletion_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TILES_GPU_IMAGE_DECODE_CACHE_H_