Pepper: Add IsAvailable() static methods to C++ wrappers to AudioInput_Dev and VideoCapture_Dev.

ppapi/cpp/dev/audio_input_dev.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 "ppapi/cpp/dev/audio_input_dev.h"
 
 #include "ppapi/c/dev/ppb_audio_input_dev.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
@@ skipping 13 matching lines @@
                                const AudioConfig& config,
                                PPB_AudioInput_Callback callback,
                                void* user_data)
     : config_(config) {
   if (has_interface<PPB_AudioInput_Dev>()) {
     PassRefFromConstructor(get_interface<PPB_AudioInput_Dev>()->Create(
         instance->pp_instance(), config.pp_resource(), callback, user_data));
   }
 }
 
+// static
+bool AudioInput_Dev::IsAvailable() {
+  return has_interface<PPB_AudioInput_Dev>();
+}
+
 bool AudioInput_Dev::StartCapture() {
   return has_interface<PPB_AudioInput_Dev>() &&
       get_interface<PPB_AudioInput_Dev>()->StartCapture(pp_resource());
 }
 
 bool AudioInput_Dev::StopCapture() {
   return has_interface<PPB_AudioInput_Dev>() &&
       get_interface<PPB_AudioInput_Dev>()->StopCapture(pp_resource());
 }
 
 }  // namespace pp