Refactor DiscardableMemory for the upcoming DiscardableMemoryAllocator.

webkit/child/webkitplatformsupport_child_impl.cc

Index: webkit/child/webkitplatformsupport_child_impl.cc
diff --git a/webkit/child/webkitplatformsupport_child_impl.cc b/webkit/child/webkitplatformsupport_child_impl.cc
index 1df9a12518946f5e4aa02fd877b45175230a1edc..849dcb7b0a8fb5ba854c02209a63a857fa4f1794 100644
--- a/webkit/child/webkitplatformsupport_child_impl.cc
+++ b/webkit/child/webkitplatformsupport_child_impl.cc
@@ -95,11 +95,7 @@ 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;
+  return WebDiscardableMemoryImpl::CreateLockedMemory(bytes).release();
 }
 
 // static