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

chrome_frame/chrome_frame_activex.cc

Index: chrome_frame/chrome_frame_activex.cc
===================================================================
--- chrome_frame/chrome_frame_activex.cc	(revision 48060)
+++ chrome_frame/chrome_frame_activex.cc	(working copy)
@@ -128,11 +128,11 @@
 
 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_);