Convert Gamepad IPC messages into mojo interface.

content/browser/renderer_host/gamepad_monitor.cc

+// Copyright (c) 2011 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 "content/browser/renderer_host/gamepad_monitor.h"
+
+#include "base/memory/shared_memory.h"
+#include "content/browser/gamepad/gamepad_service.h"
+#include "content/common/gamepad_hardware_buffer.h"
+#include "content/public/browser/browser_thread.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/system/platform_handle.h"
+
+namespace content {
+
+GamepadMonitor::GamepadMonitor() : is_started_(false) {}
+
+GamepadMonitor::~GamepadMonitor() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (is_started_)
+    GamepadService::GetInstance()->RemoveConsumer(this);
+}
+
+// static
+void GamepadMonitor::Create(device::mojom::GamepadMonitorRequest request) {
+  mojo::MakeStrongBinding(base::MakeUnique<GamepadMonitor>(),
+                          std::move(request));
+}
+
+void GamepadMonitor::OnGamepadConnected(unsigned index,
+                                        const blink::WebGamepad& gamepad) {
+  if (gamepad_observer_)
+    gamepad_observer_->GamepadConnected(index, gamepad);
+}
+
+void GamepadMonitor::OnGamepadDisconnected(unsigned index,
+                                           const blink::WebGamepad& gamepad) {
+  if (gamepad_observer_)
+    gamepad_observer_->GamepadDisconnected(index, gamepad);
+}
+
+void GamepadMonitor::GamepadStartPolling(
+    const GamepadStartPollingCallback& callback) {
+  GamepadService* service = GamepadService::GetInstance();
+  DCHECK(!is_started_);
+  if (is_started_)

[blundell, 2016/12/05 15:22:34]

You shouldn't handle a condition that you've DCHECK'd doesn't occur, so just
eliminate lines 46-47 (I see this is just copied code, but while you're
here...).

[ke.he, 2016/12/06 09:51:27]

Done.

+    return;
+
+  is_started_ = true;
+  service->ConsumerBecameActive(this);
+  base::SharedMemoryHandle renderer_handle = service->GetSharedMemoryHandle();
+  // TODO(heke): Use mojo::SharedBuffer rather than base::Sharedmemory in
+  // GamepadSharedBuffer. See crbug.com/670655 for details.
+  callback.Run(mojo::WrapSharedMemoryHandle(
+      renderer_handle, sizeof(GamepadHardwareBuffer), true /* read_only */));
+}
+
+void GamepadMonitor::GamepadStopPolling(
+    const GamepadStopPollingCallback& callback) {
+  DCHECK(is_started_);
+  if (!is_started_)

[blundell, 2016/12/05 15:22:34]

same comment as above.

[ke.he, 2016/12/06 09:51:27]

Done.

+    return;
+
+  is_started_ = false;
+  GamepadService::GetInstance()->ConsumerBecameInactive(this);
+  callback.Run();
+}
+
+void GamepadMonitor::SetObserver(
+    device::mojom::GamepadObserverPtr gamepad_observer) {
+  gamepad_observer_ = std::move(gamepad_observer);
+}
+
+}  // namespace content