Enable warning 4389 as an error on windows builds. This will make...

chrome_frame/chrome_frame_activex.cc

 // Copyright (c) 2010 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 "chrome_frame/chrome_frame_activex.h"
 
 #include <wininet.h>
 
 #include <algorithm>
 #include <map>
@@ skipping 110 matching lines @@
   if (FAILED(hr))
     return hr;
 
   // No need to call FireOnChanged at this point since nobody will be listening.
   ready_state_ = READYSTATE_LOADING;
   return S_OK;
 }
 
 ChromeFrameActivex::~ChromeFrameActivex() {
   // We expect these to be released during a call to SetClientSite(NULL).
-  DCHECK_EQ(0, onmessage_.size());
-  DCHECK_EQ(0, onloaderror_.size());
-  DCHECK_EQ(0, onload_.size());
-  DCHECK_EQ(0, onreadystatechanged_.size());
-  DCHECK_EQ(0, onextensionready_.size());
+  DCHECK_EQ(0u, onmessage_.size());
+  DCHECK_EQ(0u, onloaderror_.size());
+  DCHECK_EQ(0u, onload_.size());
+  DCHECK_EQ(0u, onreadystatechanged_.size());
+  DCHECK_EQ(0u, onextensionready_.size());
 
   if (chrome_wndproc_hook_) {
     BOOL unhook_success = ::UnhookWindowsHookEx(chrome_wndproc_hook_);
     DCHECK(unhook_success);
   }
 
   // ChromeFramePlugin::Uninitialize()
   Base::Uninitialize();
 
   TRACE_EVENT_END("chromeframe.createactivex", this, "");
@@ skipping 495 matching lines @@
   if (FAILED(hr)) {
     NOTREACHED() << "ChromeFrame BHO SetSite failed. Error:"
                  << StringPrintf(" 0x%08X", hr);
     return hr;
   }
 
   web_browser2->PutProperty(ScopedBstr(bho_class_id_as_string),
                             ScopedVariant(bho));
   return S_OK;
 }