Replace blink::WebDiscardableMemory with base::DiscardableMemory.

content/child/blink_platform_impl.h

 // Copyright 2014 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 CONTENT_CHILD_BLINK_PLATFORM_IMPL_H_
 #define CONTENT_CHILD_BLINK_PLATFORM_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 65 matching lines @@
   bool databaseSetFileSize(const blink::WebString& vfs_file_name,
                            long long size) override;
   blink::WebString signedPublicKeyAndChallengeString(
       unsigned key_size_index,
       const blink::WebString& challenge,
       const blink::WebURL& url,
       const blink::WebURL& top_origin) override;
   size_t actualMemoryUsageMB() override;
   size_t numberOfProcessors() override;
 
-  blink::WebDiscardableMemory* allocateAndLockDiscardableMemory(
-      size_t bytes) override;
   size_t maxDecodedImageBytes() override;
   uint32_t getUniqueIdForProcess() override;
   blink::WebURLLoader* createURLLoader() override;
   blink::WebSocketHandle* createWebSocketHandle() override;
   blink::WebString userAgent() override;
   blink::WebData parseDataURL(const blink::WebURL& url,
                               blink::WebString& mimetype,
                               blink::WebString& charset) override;
   blink::WebURLError cancelledError(const blink::WebURL& url) const override;
   bool isReservedIPAddress(const blink::WebString& host) const override;
@@ skipping 74 matching lines @@
   scoped_refptr<PushDispatcher> push_dispatcher_;
   scoped_ptr<PermissionDispatcher> permission_client_;
   scoped_ptr<BackgroundSyncProvider> main_thread_sync_provider_;
 
   scheduler::WebThreadBase* compositor_thread_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_BLINK_PLATFORM_IMPL_H_