Introduce PPB_AudioInput_Dev v0.3 and refactor the device enumeration code:

content/renderer/pepper/pepper_device_enumeration_host_helper.h

Index: content/renderer/pepper/pepper_device_enumeration_host_helper.h
diff --git a/content/renderer/pepper/pepper_device_enumeration_host_helper.h b/content/renderer/pepper/pepper_device_enumeration_host_helper.h
new file mode 100644
index 0000000000000000000000000000000000000000..db0af2d6f4f50a805be2ccb037b247ef9ebbf5ac
--- /dev/null
+++ b/content/renderer/pepper/pepper_device_enumeration_host_helper.h
@@ -0,0 +1,106 @@
+// Copyright (c) 2012 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.
+
+#ifndef CONTENT_RENDERER_PEPPER_PEPPER_DEVICE_ENUMERATION_HOST_HELPER_H_
+#define CONTENT_RENDERER_PEPPER_PEPPER_DEVICE_ENUMERATION_HOST_HELPER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/common/content_export.h"
+#include "ppapi/c/dev/ppb_device_ref_dev.h"
+
+namespace ppapi {
+struct DeviceRefData;
+
+namespace host {
+struct HostMessageContext;
+struct ReplyMessageContext;
+class ResourceHost;
+}
+}
+
+namespace IPC {
+class Message;
+}
+
+namespace webkit {
+namespace ppapi {
+class PluginDelegate;
+}
+}
+
+namespace content {
+
+// Resource hosts that support device enumeration can use this class to filter
+// and process PpapiHostMsg_DeviceEnumeration_* messages.
+// TODO(yzshen): Refactor ppapi::host::ResourceMessageFilter to support message
+// handling on the same thread, and then derive this class from the filter
+// class.
+class CONTENT_EXPORT PepperDeviceEnumerationHostHelper {
+ public:
+  class Delegate {
+   public:
+    virtual ~Delegate() {}
+
+    // TODO(yzshen): Move the relevant functionality out of PluginDelegate and
+    // get rid of this method.
+    virtual webkit::ppapi::PluginDelegate* GetPluginDelegate() = 0;
+  };
+
+  // |resource_host| and |delegate| must outlive this object.
+  PepperDeviceEnumerationHostHelper(ppapi::host::ResourceHost* resource_host,
+                                    Delegate* delegate,
+                                    PP_DeviceType_Dev device_type);
+  ~PepperDeviceEnumerationHostHelper();
+
+  // Returns true if the message has been handled.
+  bool HandleResourceMessage(const IPC::Message& msg,
+                             ppapi::host::HostMessageContext* context,
+                             int32_t* result);
+
+ private:
+  class ScopedRequest;
+
+  // Has a different signature than HandleResourceMessage() in order to utilize
+  // message dispatching macros.
+  int32_t InternalHandleResourceMessage(
+      const IPC::Message& msg,
+      ppapi::host::HostMessageContext* context,
+      bool* handled);
+
+  int32_t OnMsgEnumerateDevices(ppapi::host::HostMessageContext* context);
+  int32_t OnMsgMonitorDeviceChange(ppapi::host::HostMessageContext* context,
+                                   uint32_t callback_id);
+  int32_t OnMsgStopMonitoringDeviceChange(
+      ppapi::host::HostMessageContext* context);
+
+  void OnEnumerateDevicesComplete(
+      int request_id,
+      bool succeeded,
+      const std::vector<ppapi::DeviceRefData>& devices);
+  void OnNotifyDeviceChange(
+      uint32_t callback_id,
+      int request_id,
+      bool succeeded,
+      const std::vector<ppapi::DeviceRefData>& devices);
+
+  // Non-owning pointers.
+  ppapi::host::ResourceHost* resource_host_;
+  Delegate* delegate_;
+
+  PP_DeviceType_Dev device_type_;
+
+  scoped_ptr<ScopedRequest> enumerate_;
+  scoped_ptr<ScopedRequest> monitor_;
+
+  scoped_ptr<ppapi::host::ReplyMessageContext> enumerate_devices_context_;
+
+  DISALLOW_COPY_AND_ASSIGN(PepperDeviceEnumerationHostHelper);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PEPPER_PEPPER_DEVICE_ENUMERATION_HOST_HELPER_H_