Make Resource MemoryCoordinatorClient.

third_party/WebKit/Source/core/fetch/CachedMetadataHandler.h

 // Copyright 2015 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 CachedMetadataHandler_h
 #define CachedMetadataHandler_h
 
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 class CachedMetadata;
 
 // Handler class for caching operations.
 class CachedMetadataHandler : public GarbageCollectedFinalized<CachedMetadataHandler> {
 public:
     enum CacheType {
         SendToPlatform, // send cache data to blink::Platform::cacheMetadata
         CacheLocally // cache only in Resource's member variables
     };
     virtual ~CachedMetadataHandler() { }
     DEFINE_INLINE_VIRTUAL_TRACE() { }
     // Caches the given metadata in association with this resource and suggests
     // that the platform persist it. The dataTypeID is a pseudo-randomly chosen
     // identifier that is used to distinguish data generated by the caller.
     virtual void setCachedMetadata(unsigned dataTypeID, const char*, size_t, CacheType = SendToPlatform) = 0;
     // Reset existing metadata, to allow setting new data.
     virtual void clearCachedMetadata(CacheType = CacheLocally) = 0;
     // Returns cached metadata of the given type associated with this resource.

[yhirano, 2016/08/25 01:25:12]

Please add a comment saying that this metadata can be pruned at any time.

[tasak, 2016/08/25 10:33:50]

Done.

-    virtual CachedMetadata* cachedMetadata(unsigned dataTypeID) const = 0;
+    virtual PassRefPtr<CachedMetadata> cachedMetadata(unsigned dataTypeID) const = 0;
     // Returns the encoding to which the cache is specific.
     virtual String encoding() const = 0;
 
 protected:
     CachedMetadataHandler() { }
 };
 } // namespace blink
 
 #endif // CachedMetadataHandler_h