Use DiscardableMemoryManager on Android.

base/memory/discardable_memory_linux.cc

 // Copyright 2013 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 "base/memory/discardable_memory.h"
 
 #include "base/logging.h"
 #include "base/memory/discardable_memory_emulated.h"
 #include "base/memory/discardable_memory_malloc.h"
 
@@ skipping 43 matching lines @@
 
       return memory.PassAs<DiscardableMemory>();
     }
   }
 
   NOTREACHED();
   return scoped_ptr<DiscardableMemory>();
 }
 
 // static
-bool DiscardableMemory::PurgeForTestingSupported() {
-  return true;
+bool DiscardableMemory::PurgeForTestingSupported(DiscardableMemoryType type) {
+  switch (type) {
+    case DISCARDABLE_MEMORY_TYPE_EMULATED:
+      return true;
+    default:
+      return false;
+  }
 }
 
 // static
-void DiscardableMemory::PurgeForTesting() {
-  internal::DiscardableMemoryEmulated::PurgeForTesting();
+void DiscardableMemory::PurgeForTesting(DiscardableMemoryType type) {
+  switch (type) {
+    case DISCARDABLE_MEMORY_TYPE_EMULATED:
+      internal::DiscardableMemoryEmulated::PurgeForTesting();
+      return;
+    default:
+      NOTREACHED();
+  }
 }
 
 }  // namespace base