base: Discardable memory types.

webkit/child/webkitplatformsupport_child_impl.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 "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"
@@ skipping 75 matching lines @@
 }
 
 void WebKitPlatformSupportChildImpl::didStopWorkerRunLoop(
     const blink::WebWorkerRunLoop& runLoop) {
   WorkerTaskRunner* worker_task_runner = WorkerTaskRunner::Instance();
   worker_task_runner->OnWorkerRunLoopStopped(runLoop);
 }
 
 blink::WebDiscardableMemory*
 WebKitPlatformSupportChildImpl::allocateAndLockDiscardableMemory(size_t bytes) {
-  if (!base::DiscardableMemory::SupportedNatively())
+  base::DiscardableMemoryType type = base::DiscardableMemory::GetType();

[Philippe, 2013/12/18 09:07:47]

Just realized that there was this SupportedNatively() check here :) Does this
mean that emulated DM isn't used (yet)?

[reveman, 2013/12/18 19:44:25]

Existing code in blink that uses discardable memory doesn't get to use emulated
yet. Skia and the new image decode cache that is implemented in skia gets to use
it though.

The plan is to enable this later once we've transitioned to using the new image
cache everywhere.

+  if (type == base::DISCARDABLE_MEMORY_TYPE_EMULATED)
     return NULL;
   return WebDiscardableMemoryImpl::CreateLockedMemory(bytes).release();
 }
 
 // static
 void WebKitPlatformSupportChildImpl::DestroyCurrentThread(void* thread) {
   WebThreadImplForMessageLoop* impl =
       static_cast<WebThreadImplForMessageLoop*>(thread);
   delete impl;
 }
 
 }  // namespace webkit_glue