[Mac] A couple of improvements for DiscardableMemory

base/memory/discardable_memory_emulated.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_emulated.h"
 
 #include "base/lazy_instance.h"
 #include "base/memory/discardable_memory_manager.h"
 
 namespace base {
@@ skipping 38 matching lines @@
 void DiscardableMemoryEmulated::UnregisterMemoryPressureListeners() {
   g_shared_state.Pointer()->manager.UnregisterMemoryPressureListener();
 }
 
 // static
 void DiscardableMemoryEmulated::PurgeForTesting() {
   g_shared_state.Pointer()->manager.PurgeAll();
 }
 
 bool DiscardableMemoryEmulated::Initialize() {
-  return Lock() == DISCARDABLE_MEMORY_LOCK_STATUS_PURGED;
+  return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 }
 
 DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
   DCHECK(!is_locked_);
 
   bool purged = false;
   if (!g_shared_state.Pointer()->manager.AcquireLock(this, &purged))
     return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 
   is_locked_ = true;
@@ skipping 20 matching lines @@
   memory_.reset(new uint8[bytes_]);
   return false;
 }
 
 void DiscardableMemoryEmulated::Purge() {
   memory_.reset();
 }
 
 }  // namespace internal
 }  // namespace base