Enable size_t to int truncation warnings in PPAPI

ppapi/proxy/device_enumeration_resource_helper.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/device_enumeration_resource_helper.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "ipc/ipc_message.h"
@@ skipping 128 matching lines @@
     uint32_t callback_id,
     const std::vector<DeviceRefData>& devices) {
   if (monitor_callback_id_ != callback_id) {
     // A new callback or NULL has been set.
     return;
   }
 
   CHECK(monitor_callback_.get());
 
   scoped_ptr<PP_Resource[]> elements;
-  uint32_t size = devices.size();
+  uint32_t size = static_cast<uint32_t>(devices.size());
   if (size > 0) {
     elements.reset(new PP_Resource[size]);
     for (size_t index = 0; index < size; ++index) {
       PPB_DeviceRef_Shared* device_object = new PPB_DeviceRef_Shared(
           OBJECT_IS_PROXY, owner_->pp_instance(), devices[index]);
       elements[index] = device_object->GetReference();
     }
   }
 
   monitor_callback_->RunOnTargetThread(monitor_user_data_, size,
@@ skipping 15 matching lines @@
         OBJECT_IS_PROXY, owner_->pp_instance(), devices[i]));
   }
   if (!writer.StoreResourceVector(device_resources))
     return PP_ERROR_FAILED;
 
   return PP_OK;
 }
 
 }  // namespace proxy
 }  // namespace ppapi