Setup DiscardableMemory in the ash process

ash/mus/window_manager_application.cc

 // Copyright 2015 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 "ash/mus/window_manager_application.h"
 
 #include <utility>
 
 #include "ash/common/mojo_interface_factory.h"
 #include "ash/common/system/chromeos/power/power_status.h"
 #include "ash/common/wm_shell.h"
 #include "ash/mus/network_connect_delegate_mus.h"
 #include "ash/mus/window_manager.h"
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/network/network_connect.h"
 #include "chromeos/network/network_handler.h"
 #include "chromeos/system/fake_statistics_provider.h"
+#include "components/discardable_memory/client/client_discardable_shared_memory_manager.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/dbus/bluez_dbus_manager.h"
 #include "services/service_manager/public/cpp/connection.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "services/service_manager/public/cpp/service_context.h"
 #include "services/tracing/public/cpp/provider.h"
 #include "services/ui/common/accelerator_util.h"
+#include "services/ui/public/interfaces/constants.mojom.h"
 #include "ui/aura/env.h"
 #include "ui/aura/mus/window_tree_client.h"
 #include "ui/events/event.h"
 #include "ui/message_center/message_center.h"
 #include "ui/views/mus/aura_init.h"
 
 namespace ash {
 namespace mus {
 
 WindowManagerApplication::WindowManagerApplication() {}
@@ skipping 60 matching lines @@
   chromeos::NetworkConnect::Shutdown();
   network_connect_delegate_.reset();
   chromeos::NetworkHandler::Shutdown();
   device::BluetoothAdapterFactory::Shutdown();
   bluez::BluezDBusManager::Shutdown();
   chromeos::DBusThreadManager::Shutdown();
   message_center::MessageCenter::Shutdown();
 }
 
 void WindowManagerApplication::OnStart() {
+  io_thread_ = base::MakeUnique<base::Thread>("IOThread");
+  base::Thread::Options thread_options(base::MessageLoop::TYPE_IO, 0);
+  thread_options.priority = base::ThreadPriority::NORMAL;
+  CHECK(io_thread_->StartWithOptions(thread_options));
+  auto io_task_runner = io_thread_->task_runner();
   aura_init_ = base::MakeUnique<views::AuraInit>(
       context()->connector(), context()->identity(), "ash_mus_resources.pak",
-      "ash_mus_resources_200.pak", nullptr,
+      "ash_mus_resources_200.pak", io_task_runner,

[James Cook, 2017/03/09 21:00:21]

Can you add a comment somewhere (maybe in the AuraInit constructor) that
emphasizes that the IO task runner parameter really is for IPC and not for file
IO? At first I thought the task runner was related to loading the .pak files and
hence should be the FILE thread.

       views::AuraInit::Mode::AURA_MUS_WINDOW_MANAGER);
   window_manager_.reset(new WindowManager(context()->connector()));
 
+  discardable_memory::mojom::DiscardableSharedMemoryManagerPtr manager_ptr;

[James Cook, 2017/03/09 21:00:21]

This block of code seems like it should live down in //ui/views/mus. It seems
like discardable memory could be used by anyone who uses skia. AuraInit
sometimes constructs a MusClient and MusClient creates a discardable memory
allocator, so it seems like it should go down there.  WDYT?

[Peng, 2017/03/09 21:35:43]

+sky, for his opinion.

+  context()->connector()->BindInterface(ui::mojom::kServiceName, &manager_ptr);
+  discardable_shared_memory_manager_ = base::MakeUnique<
+      discardable_memory::ClientDiscardableSharedMemoryManager>(
+      std::move(manager_ptr), io_task_runner);
+  base::DiscardableMemoryAllocator::SetInstance(
+      discardable_shared_memory_manager_.get());
+
   tracing_.Initialize(context()->connector(), context()->identity().name());
 
   std::unique_ptr<aura::WindowTreeClient> window_tree_client =
       base::MakeUnique<aura::WindowTreeClient>(
-          context()->connector(), window_manager_.get(), window_manager_.get());
+          context()->connector(), window_manager_.get(), window_manager_.get(),
+          nullptr, io_task_runner);
   window_tree_client->ConnectAsWindowManager();
 
   const size_t kMaxNumberThreads = 3u;  // Matches that of content.
   const char kThreadNamePrefix[] = "MashBlocking";
   blocking_pool_ = new base::SequencedWorkerPool(
       kMaxNumberThreads, kThreadNamePrefix, base::TaskPriority::USER_VISIBLE);
   InitWindowManager(std::move(window_tree_client), blocking_pool_);
 }
 
 bool WindowManagerApplication::OnConnect(
     const service_manager::ServiceInfo& remote_info,
     service_manager::InterfaceRegistry* registry) {
   // Register services used in both classic ash and mash.
   mojo_interface_factory::RegisterInterfaces(
       registry, base::ThreadTaskRunnerHandle::Get());
   return true;
 }
 
 }  // namespace mus
 }  // namespace ash