Allow extensions which can run without NPAPI to run under Windows 8 Metro.

chrome/browser/extensions/requirements_checker.cc

Index: chrome/browser/extensions/requirements_checker.cc
diff --git a/chrome/browser/extensions/requirements_checker.cc b/chrome/browser/extensions/requirements_checker.cc
index 516f5b0e083ba2d4c2533443ee47429f00cddbde..d350e0db1b7cb48db07348580632408ed8ec9b3b 100644
--- a/chrome/browser/extensions/requirements_checker.cc
+++ b/chrome/browser/extensions/requirements_checker.cc
@@ -15,6 +15,10 @@
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if defined(OS_WIN)
+#include "base/win/metro.h"
+#endif // defined(OS_WIN)
+
 namespace extensions {
 
 RequirementsChecker::RequirementsChecker()
@@ -36,6 +40,12 @@ void RequirementsChecker::Check(scoped_refptr<const Extension> extension,
     errors_.push_back(
         l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
 #endif  // defined(OS_CHROMEOS)
+#if defined(OS_WIN)
+    if (base::win::IsMetroProcess()) {
+      errors_.push_back(
+          l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
+    }
+#endif  // defined(OS_WIN)
   }
 
   if (requirements.webgl) {