Add implementation for WebKit::WebDiscardableMemory and WebKitPlatformSupportImpl::allocateAndLockDiscardableMemory

https://bugs.webkit.org/show_bug.cgi?id=107183 added WebDiscardableMemory and
the allocateAndLockDiscardableMemory() call
This CL adds implementation for that.

BUG=164052

Review URL: https://codereview.chromium.org/12045053

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@178711 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 103 insertions, 0 deletions

diff --git a/webkit/glue/web_discardable_memory_impl.cc b/webkit/glue/web_discardable_memory_impl.cc
new file mode 100644
index 0000000..d4c3ee2
--- /dev/null
+++ b/webkit/glue/web_discardable_memory_impl.cc
@@ -0,0 +1,41 @@
+// 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 "webkit/glue/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/glue/web_discardable_memory_impl.h b/webkit/glue/web_discardable_memory_impl.h
new file mode 100644
index 0000000..7f92aff
--- /dev/null
+++ b/webkit/glue/web_discardable_memory_impl.h
@@ -0,0 +1,44 @@
+// 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.
+
+#ifndef WEBKIT_GLUE_WEB_DISCARDABLE_MEMORY_IMPL_H_
+#define WEBKIT_GLUE_WEB_DISCARDABLE_MEMORY_IMPL_H_
+
+#include "base/memory/discardable_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebDiscardableMemory.h"
+#include "webkit/glue/webkit_glue_export.h"
+
+namespace WebKit {
+class WebDiscardableMemory;
+}
+
+namespace webkit_glue {
+
+// Implementation of WebDiscardableMemory that is responsible for allocating
+// discardable memory.
+class WEBKIT_GLUE_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_GLUE_WEB_DISCARDABLE_MEMORY_IMPL_H_
diff --git a/webkit/glue/webkit_glue.gypi b/webkit/glue/webkit_glue.gypi
index 814d5c5..ad0b4de 100644
--- a/webkit/glue/webkit_glue.gypi
+++ b/webkit/glue/webkit_glue.gypi
@@ -314,6 +314,8 @@
         'simple_webmimeregistry_impl.h',
         'touch_fling_gesture_curve.cc',
         'touch_fling_gesture_curve.h',
+        'web_discardable_memory_impl.cc',
+        'web_discardable_memory_impl.h',
         'webclipboard_impl.cc',
         'webclipboard_impl.h',
         'webcookie.cc',
diff --git a/webkit/glue/webkitplatformsupport_impl.cc b/webkit/glue/webkitplatformsupport_impl.cc
index 6ebd52a..409d700 100644
--- a/webkit/glue/webkitplatformsupport_impl.cc
+++ b/webkit/glue/webkitplatformsupport_impl.cc
@@ -11,6 +11,7 @@
 #include "base/allocator/allocator_extension.h"
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
+#include "base/memory/discardable_memory.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/message_loop.h"
@@ -30,6 +31,7 @@
 #include "grit/webkit_strings.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebCookie.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebData.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebDiscardableMemory.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGestureCurve.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebString.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebURL.h"
@@ -42,6 +44,7 @@
 #include "webkit/base/file_path_string_conversions.h"
 #include "webkit/compositor_bindings/web_compositor_support_impl.h"
 #include "webkit/glue/touch_fling_gesture_curve.h"
+#include "webkit/glue/web_discardable_memory_impl.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/glue/websocketstreamhandle_impl.h"
 #include "webkit/glue/webthread_impl.h"
@@ -928,4 +931,15 @@ WebKit::WebGestureCurve* WebKitPlatformSupportImpl::createFlingAnimationCurve(
   return TouchFlingGestureCurve::CreateForTouchPad(velocity, cumulative_scroll);
 }
 
+WebKit::WebDiscardableMemory*
+    WebKitPlatformSupportImpl::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;
+}
+
 }  // namespace webkit_glue
diff --git a/webkit/glue/webkitplatformsupport_impl.h b/webkit/glue/webkitplatformsupport_impl.h
index 8f858a2..8d928ba 100644
--- a/webkit/glue/webkitplatformsupport_impl.h
+++ b/webkit/glue/webkitplatformsupport_impl.h
@@ -118,6 +118,8 @@ class WEBKIT_GLUE_EXPORT WebKitPlatformSupportImpl :
   virtual WebKit::WebThread* createThread(const char* name);
   virtual WebKit::WebThread* currentThread();
   virtual WebKit::WebCompositorSupport* compositorSupport();
+  virtual WebKit::WebDiscardableMemory* allocateAndLockDiscardableMemory(
+      size_t bytes);
 
 
   // Embedder functions. The following are not implemented by the glue layer and