Replace blink::WebDiscardableMemory with base::DiscardableMemory.

third_party/WebKit/public/platform/Platform.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 52 matching lines @@
 namespace blink {
 
 class WebAudioBus;
 class WebBlobRegistry;
 class WebCanvasCaptureHandler;
 class WebClipboard;
 class WebCompositorSupport;
 class WebCookieJar;
 class WebCrypto;
 class WebDatabaseObserver;
-class WebDiscardableMemory;
 class WebPlatformEventListener;
 class WebFallbackThemeEngine;
 class WebFileSystem;
 class WebFileUtilities;
 class WebFlingAnimator;
 class WebGeofencingProvider;
 class WebGestureCurve;
 class WebGraphicsContext3DProvider;
 class WebIDBFactory;
 class WebInstalledApp;
@@ skipping 184 matching lines @@
     {
         return WebString();
     }
 
     // Same as above, but always returns actual value, without any caches.
     virtual size_t actualMemoryUsageMB() { return 0; }
 
     // Return the number of of processors of the current machine.
     virtual size_t numberOfProcessors() { return 0; }
 
-    // Allocates discardable memory. May return nullptr, even if the platform supports
-    // discardable memory. If nonzero, however, then the WebDiscardableMmeory is
-    // returned in an locked state. You may use its underlying data() member
-    // directly, taking care to unlock it when you are ready to let it become
-    // discardable.
-    virtual WebDiscardableMemory* allocateAndLockDiscardableMemory(size_t bytes) { return nullptr; }
-
     static const size_t noDecodedImageByteLimit = static_cast<size_t>(-1);
 
     // Returns the maximum amount of memory a decoded image should be allowed.
     // See comments on ImageDecoder::m_maxDecodedBytes.
     virtual size_t maxDecodedImageBytes() { return noDecodedImageByteLimit; }
 
     // Process -------------------------------------------------------------
 
     // Returns a unique identifier for a process. This may not necessarily be
     // the process's process ID.
@@ skipping 327 matching lines @@
 protected:
     Platform();
     virtual ~Platform() { }
 
     WebThread* m_mainThread;
 };
 
 } // namespace blink
 
 #endif