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

ppapi/cpp/dev/video_capture_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/video_capture_dev.h"
 
 #include "ppapi/c/dev/ppb_video_capture_dev.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
@@ skipping 16 matching lines @@
       instance.pp_instance()));
 }
 
 VideoCapture_Dev::VideoCapture_Dev(PP_Resource resource) : Resource(resource) {
 }
 
 VideoCapture_Dev::VideoCapture_Dev(const VideoCapture_Dev& other)
     : Resource(other) {
 }
 
+// static
+bool VideoCapture_Dev::IsAvailable() {
+  return has_interface<PPB_VideoCapture_Dev>();
+}
+
 int32_t VideoCapture_Dev::StartCapture(
     const PP_VideoCaptureDeviceInfo_Dev& requested_info,
     uint32_t buffer_count) {
   if (!has_interface<PPB_VideoCapture_Dev>())
     return PP_ERROR_FAILED;
   return get_interface<PPB_VideoCapture_Dev>()->StartCapture(
       pp_resource(), &requested_info, buffer_count);
 }
 
 int32_t VideoCapture_Dev::ReuseBuffer(uint32_t buffer) {
   if (!has_interface<PPB_VideoCapture_Dev>())
     return PP_ERROR_FAILED;
   return get_interface<PPB_VideoCapture_Dev>()->ReuseBuffer(
       pp_resource(), buffer);
 }
 
 int32_t VideoCapture_Dev::StopCapture(){
   if (!has_interface<PPB_VideoCapture_Dev>())
     return PP_ERROR_FAILED;
   return get_interface<PPB_VideoCapture_Dev>()->StopCapture(pp_resource());
 }
 
 }  // namespace pp