4 files changed, 101 insertions, 0 deletions
diff --git a/webkit/child/web_discardable_memory_impl.cc b/webkit/child/web_discardable_memory_impl.cc
new file mode 100644
index 0000000..0e2663c
--- /dev/null
+++ b/webkit/child/web_discardable_memory_impl.cc
@@ -0,0 +1,41 @@
+// 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 "webkit/child/web_discardable_memory_impl.h"
+
+namespace webkit_glue {
+
+WebDiscardableMemoryImpl::WebDiscardableMemoryImpl()
+    : discardable_(new base::DiscardableMemory()) {
+}
+
+WebDiscardableMemoryImpl::~WebDiscardableMemoryImpl() {}
+
+bool WebDiscardableMemoryImpl::InitializeAndLock(size_t size) {
+  return discardable_->InitializeAndLock(size);
+}
+
+bool WebDiscardableMemoryImpl::lock() {
+  base::LockDiscardableMemoryStatus status = discardable_->Lock();
+  switch (status) {
+    case base::DISCARDABLE_MEMORY_SUCCESS:
+      return true;
+    case base::DISCARDABLE_MEMORY_PURGED:
+      discardable_->Unlock();
+      return false;
+    default:
+      discardable_.reset();
+      return false;
+  }
+}
+
+void* WebDiscardableMemoryImpl::data() {
+  return discardable_->Memory();
+}
+
+void WebDiscardableMemoryImpl::unlock() {
+  discardable_->Unlock();
+}
+
+}  // namespace webkit_glue
diff --git a/webkit/child/web_discardable_memory_impl.h b/webkit/child/web_discardable_memory_impl.h
new file mode 100644
index 0000000..f2ad328
--- /dev/null
+++ b/webkit/child/web_discardable_memory_impl.h
@@ -0,0 +1,44 @@
+// 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.
+
+#ifndef WEBKIT_CHILD_WEB_DISCARDABLE_MEMORY_IMPL_H_
+#define WEBKIT_CHILD_WEB_DISCARDABLE_MEMORY_IMPL_H_
+
+#include "base/memory/discardable_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "third_party/WebKit/public/platform/WebDiscardableMemory.h"
+#include "webkit/child/webkit_child_export.h"
+
+namespace WebKit {
+class WebDiscardableMemory;
+}
+
+namespace webkit_glue {
+
+// Implementation of WebDiscardableMemory that is responsible for allocating
+// discardable memory.
+class WEBKIT_CHILD_EXPORT WebDiscardableMemoryImpl
+    : NON_EXPORTED_BASE(public WebKit::WebDiscardableMemory) {
+ public:
+  WebDiscardableMemoryImpl();
+  virtual ~WebDiscardableMemoryImpl();
+
+  // WebKit::WebDiscardableMemory implementation.
+  virtual bool lock();
+  virtual void unlock();
+  virtual void* data();
+
+  // Initialize the WebDiscardableMemoryImpl object and lock the memory.
+  // Returns true on success. No memory is allocated if this call returns
+  // false. This call should only be called once.
+  bool InitializeAndLock(size_t size);
+
+ private:
+  scoped_ptr<base::DiscardableMemory> discardable_;
+  DISALLOW_COPY_AND_ASSIGN(WebDiscardableMemoryImpl);
+};
+
+}  // namespace webkit_glue
+
+#endif  // WEBKIT_CHILD_WEB_DISCARDABLE_MEMORY_IMPL_H_
diff --git a/webkit/child/webkitplatformsupport_child_impl.cc b/webkit/child/webkitplatformsupport_child_impl.cc
index 02ee5aa..1df9a12 100644
--- a/webkit/child/webkitplatformsupport_child_impl.cc
+++ b/webkit/child/webkitplatformsupport_child_impl.cc
@@ -4,8 +4,10 @@
 
 #include "webkit/child/webkitplatformsupport_child_impl.h"
 
+#include "base/memory/discardable_memory.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "webkit/child/fling_curve_configuration.h"
+#include "webkit/child/web_discardable_memory_impl.h"
 #include "webkit/child/webthread_impl.h"
 #include "webkit/child/worker_task_runner.h"
 
@@ -89,6 +91,17 @@ void WebKitPlatformSupportChildImpl::didStopWorkerRunLoop(
   worker_task_runner->OnWorkerRunLoopStopped(runLoop);
 }
 
+WebKit::WebDiscardableMemory*
+WebKitPlatformSupportChildImpl::allocateAndLockDiscardableMemory(size_t bytes) {
+  if (!base::DiscardableMemory::Supported())
+    return NULL;
+  scoped_ptr<WebDiscardableMemoryImpl> discardable(
+      new WebDiscardableMemoryImpl());
+  if (discardable->InitializeAndLock(bytes))
+    return discardable.release();
+  return NULL;
+}
+
 // static
 void WebKitPlatformSupportChildImpl::DestroyCurrentThread(void* thread) {
   WebThreadImplForMessageLoop* impl =
diff --git a/webkit/child/webkitplatformsupport_child_impl.h b/webkit/child/webkitplatformsupport_child_impl.h
index 21812b2..abb6338 100644
--- a/webkit/child/webkitplatformsupport_child_impl.h
+++ b/webkit/child/webkitplatformsupport_child_impl.h
@@ -51,6 +51,9 @@ class WEBKIT_CHILD_EXPORT WebKitPlatformSupportChildImpl :
   virtual void didStopWorkerRunLoop(
       const WebKit::WebWorkerRunLoop& runLoop) OVERRIDE;
 
+  virtual WebKit::WebDiscardableMemory* allocateAndLockDiscardableMemory(
+      size_t bytes);
+
  private:
   static void DestroyCurrentThread(void*);