Add "64-bit" to Chrome's 'about' page.

Finding whether you are running 64-bit or 32-bit is proving tricky for users
since the chrome://version page is not linked anywhere.

This adds "64-bit" string to the chrome://chrome page for 64-bit builds.

BUG=381246

Review URL: https://codereview.chromium.org/326773003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276592 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/webui/help/help_handler.cc

@@ -79,6 +79,10 @@ base::string16 BuildBrowserVersionString() {
   browser_version += ")";
 #endif
 
+#if defined(ARCH_CPU_64_BITS)
+  browser_version += " (64-bit)";
+#endif
+
   return base::UTF8ToUTF16(browser_version);
 }