Message receiver on browser side that holds/starts the gamepad data provider

content/browser/renderer_host/gamepad_browser_message_filter.cc

Index: content/browser/renderer_host/gamepad_browser_message_filter.cc
diff --git a/content/browser/renderer_host/gamepad_browser_message_filter.cc b/content/browser/renderer_host/gamepad_browser_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..93f1402472f081fee6bcfee3de35ef787278317c
--- /dev/null
+++ b/content/browser/renderer_host/gamepad_browser_message_filter.cc
@@ -0,0 +1,49 @@
+// 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_browser_message_filter.h"
+
+#include "content/common/gamepad_messages.h"
+
+GamepadBrowserMessageFilter::GamepadBrowserMessageFilter() {
+}
+
+GamepadBrowserMessageFilter::~GamepadBrowserMessageFilter() {
+}
+
+bool GamepadBrowserMessageFilter::OnMessageReceived(
+    const IPC::Message& message,
+    bool* message_was_ok) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(GamepadBrowserMessageFilter,
+                           message,
+                           *message_was_ok)
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(GamepadHostMsg_StartPolling,

[jam, 2011/11/24 23:16:02]

you only need to use IPC_MESSAGE_HANDLER_DELAY_REPLY when the sync message can't
be responded to in the dispatcher function. in these cases, you don't need it
since you always have the result ready. see
http://www.chromium.org/developers/design-documents/inter-process-communication

[scottmg, 2011/11/24 23:54:51]

Done. (and sweet, much tidier!)

+                                    OnGamepadStartPolling)
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(GamepadHostMsg_StopPolling,
+                                    OnGamepadStopPolling)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+  return handled;
+}
+
+void GamepadBrowserMessageFilter::OnGamepadStartPolling(
+    IPC::Message* reply_msg) {
+  if (!provider_) {
+    provider_ = new gamepad::Provider(NULL);
+    provider_->Start();
+  }
+  base::SharedMemoryHandle renderer_handle =
+        provider_->GetRendererSharedMemoryHandle(peer_handle());
+  GamepadHostMsg_StartPolling::WriteReplyParams(reply_msg, renderer_handle);
+  Send(reply_msg);
+}
+
+void GamepadBrowserMessageFilter::OnGamepadStopPolling(
+    IPC::Message* reply_msg) {
+  DCHECK(provider_);
+  // TODO(scottmg) Remove this message entirely?
+  // Stop is currently handled by the refcount on provider_.
+  Send(reply_msg);
+}