Enable size_t to int truncation warnings in PPAPI

ppapi/proxy/websocket_resource_unittest.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 "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/ppb_var.h"
 #include "ppapi/c/ppb_websocket.h"
 #include "ppapi/proxy/locking_resource_releaser.h"
@@ skipping 29 matching lines @@
 
 PP_CompletionCallback MakeCallback() {
   g_callback_called = false;
   g_callback_result = PP_OK;
   return PP_MakeCompletionCallback(Callback, NULL);
 }
 
 PP_Var MakeStringVar(const std::string& string) {
   if (!ppb_var_)
     ppb_var_ = ppapi::PPB_Var_Shared::GetVarInterface1_2();
-  return ppb_var_->VarFromUtf8(string.c_str(), string.length());
+  return ppb_var_->VarFromUtf8(string.c_str(),
+                               static_cast<uint32_t>(string.length()));
 }
 
 }  // namespace
 
 
 // Does a test of Connect().
 TEST_F(WebSocketResourceTest, Connect) {
   const PPB_WebSocket_1_0* websocket_iface =
       thunk::GetPPB_WebSocket_1_0_Thunk();
 
@@ skipping 95 matching lines @@
   error_reply_params.set_result(PP_OK);
   PluginMessageFilter::DispatchResourceReplyForTest(
       error_reply_params, PpapiPluginMsg_WebSocket_ErrorReply());
 
   EXPECT_EQ(PP_ERROR_FAILED, g_callback_result);
   EXPECT_TRUE(g_callback_called);
 }
 
 }  // namespace proxy
 }  // namespace ppapi