Update ppapi/ to use scoped_refptr<T>::get() rather than implicit "operator T*"

ppapi/proxy/resource_creation_proxy.cc

 // 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.
 
 #include "ppapi/proxy/resource_creation_proxy.h"
 
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_size.h"
 #include "ppapi/c/trusted/ppb_image_data_trusted.h"
 #include "ppapi/proxy/audio_input_resource.h"
@@ skipping 210 matching lines @@
     uint32_t sample_frame_count) {
   return PPB_AudioConfig_Shared::Create(
       OBJECT_IS_PROXY, instance, sample_rate, sample_frame_count);
 }
 
 PP_Resource ResourceCreationProxy::CreateFileChooser(
     PP_Instance instance,
     PP_FileChooserMode_Dev mode,
     const PP_Var& accept_types) {
   scoped_refptr<StringVar> string_var = StringVar::FromPPVar(accept_types);
-  std::string str = string_var ? string_var->value() : std::string();
-  return (new FileChooserResource(GetConnection(), instance, mode,
-                                  str.c_str()))->GetReference();
+  std::string str = string_var.get() ? string_var->value() : std::string();
+  return (new FileChooserResource(GetConnection(), instance, mode, str.c_str()))
+      ->GetReference();
 }
 
 PP_Resource ResourceCreationProxy::CreateGraphics2D(PP_Instance instance,
                                                     const PP_Size* size,
                                                     PP_Bool is_always_opaque) {
   return (new Graphics2DResource(GetConnection(), instance, *size,
                                  is_always_opaque))->GetReference();
 }
 
 PP_Resource ResourceCreationProxy::CreateGraphics3D(
@@ skipping 175 matching lines @@
 bool ResourceCreationProxy::OnMessageReceived(const IPC::Message& msg) {
   return false;
 }
 
 Connection ResourceCreationProxy::GetConnection() {
   return Connection(PluginGlobals::Get()->GetBrowserSender(), dispatcher());
 }
 
 }  // namespace proxy
 }  // namespace ppapi