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

chrome/browser/extensions/requirements_checker.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 "chrome/browser/extensions/requirements_checker.h"
 
 #include "base/bind.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/gpu_feature_checker.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/manifest.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/gpu_feature_type.h"
 #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()
     : pending_requirement_checks_(0) {
 }
 
 RequirementsChecker::~RequirementsChecker() {
 }
 
 void RequirementsChecker::Check(scoped_refptr<const Extension> extension,
     base::Callback<void(std::vector<std::string> errors)> callback) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   callback_ = callback;
   const Extension::Requirements& requirements = extension->requirements();
 
   if (requirements.npapi) {
 #if defined(OS_CHROMEOS)
     errors_.push_back(
         l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
 #endif  // defined(OS_CHROMEOS)
+#if defined(OS_WIN)
+    if (base::win::IsMetroProcess()) {

[Wez, 2012/09/19 06:34:14]

If we assume that it doesn't make sense for an extension with no NPAPI plugins
to specify that it requires NPAPI then we can simplify this clause to avoid
duplicating platform-specific blocks.

[Aaron Boodman, 2012/09/19 21:34:52]

I don't think that is a good assumption.

+      errors_.push_back(
+          l10n_util::GetStringUTF8(IDS_EXTENSION_NPAPI_NOT_SUPPORTED));
+    }
+#endif  // defined(OS_WIN)
   }
 
   if (requirements.webgl) {
     ++pending_requirement_checks_;
     webgl_checker_ = new GPUFeatureChecker(
       content::GPU_FEATURE_TYPE_WEBGL,
       base::Bind(&RequirementsChecker::SetWebGLAvailability,
                  AsWeakPtr()));
   }
 
@@ skipping 40 matching lines @@
   if (--pending_requirement_checks_ == 0) {
     content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
                                      base::Bind(callback_, errors_));
     // Reset the callback so any ref-counted bound parameters will get released.
     callback_.Reset();
     errors_.clear();
   }
 }
 
 }  // namespace extensions