base: Discardable memory types.

base/memory/discardable_memory_win.cc

 // Copyright (c) 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/lazy_instance.h"
+#include "base/logging.h"
 #include "base/memory/discardable_memory_emulated.h"
 
 namespace base {
+namespace {
+
+struct SupportedTypeVector {
+  SupportedTypeVector() {
+    v.push_back(DISCARDABLE_MEMORY_EMULATED);
+  }
+  std::vector<DiscardableMemoryType> v;
+};
+LazyInstance<SupportedTypeVector>::Leaky g_supported_types =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
 
 // static
-bool DiscardableMemory::SupportedNatively() {
-  return false;
+const std::vector<DiscardableMemoryType>&
+    DiscardableMemory::GetSupportedTypes() {
+  return g_supported_types.Get().v;
 }
 
 // static
 scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemory(
     size_t size) {
-  scoped_ptr<internal::DiscardableMemoryEmulated> memory(
-      new internal::DiscardableMemoryEmulated(size));
-  if (!memory->Initialize())
-    return scoped_ptr<DiscardableMemory>();
+  switch (GetType()) {
+    case DISCARDABLE_MEMORY_NONE:
+    case DISCARDABLE_MEMORY_ANDROID:
+    case DISCARDABLE_MEMORY_MAC:
+      return scoped_ptr<DiscardableMemory>();
+    case DISCARDABLE_MEMORY_EMULATED: {
+      scoped_ptr<internal::DiscardableMemoryEmulated> memory(
+          new internal::DiscardableMemoryEmulated(size));
+      if (!memory->Initialize())
+        return scoped_ptr<DiscardableMemory>();
 
-  return memory.PassAs<DiscardableMemory>();
+      return memory.PassAs<DiscardableMemory>();
+    }
+  }
+
+  NOTREACHED();
+  return scoped_ptr<DiscardableMemory>();
 }
 
 // static
 bool DiscardableMemory::PurgeForTestingSupported() {
   return true;
 }
 
 // static
 void DiscardableMemory::PurgeForTesting() {
   internal::DiscardableMemoryEmulated::PurgeForTesting();
 }
 
 }  // namespace base