Enable size_t to int truncation warnings in PPAPI

ppapi/proxy/ppp_instance_proxy_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/synchronization/waitable_event.h"
 #include "ipc/ipc_message_utils.h"
 #include "ppapi/c/pp_var.h"
 #include "ppapi/c/ppb_core.h"
 #include "ppapi/c/ppb_fullscreen.h"
 #include "ppapi/c/ppb_url_loader.h"
@@ skipping 122 matching lines @@
   expected_argn.push_back("Hello");
   expected_argn.push_back("world.");
   expected_argv.push_back("elloHay");
   expected_argv.push_back("orldway.");
   std::vector<const char*> argn_to_pass, argv_to_pass;
   CHECK(expected_argn.size() == expected_argv.size());
   for (size_t i = 0; i < expected_argn.size(); ++i) {
     argn_to_pass.push_back(expected_argn[i].c_str());
     argv_to_pass.push_back(expected_argv[i].c_str());
   }
-  uint32_t expected_argc = expected_argn.size();
+  uint32_t expected_argc = static_cast<uint32_t>(expected_argn.size());
   bool_to_return = PP_TRUE;
   ResetReceived();
   // Tell the host resource tracker about the instance.
   host().resource_tracker().DidCreateInstance(expected_instance);
   EXPECT_EQ(bool_to_return, ppp_instance->DidCreate(expected_instance,
                                                     expected_argc,
                                                     &argn_to_pass[0],
                                                     &argv_to_pass[0]));
   EXPECT_EQ(received_instance, expected_instance);
   EXPECT_EQ(received_argc, expected_argc);
@@ skipping 34 matching lines @@
   //  TODO(dmichael): Need to mock out a resource Tracker to be able to test
   //                  HandleResourceLoad. It also requires
   //                  PPB_Core.AddRefResource and for PPB_URLLoader to be
   //                  registered.
 
   host().resource_tracker().DidDeleteInstance(expected_instance);
 }
 
 }  // namespace proxy
 }  // namespace ppapi