Implement FeatureProvider for ExtensionAPI.

chrome/common/extensions/permission_feature.cc

Index: chrome/common/extensions/permission_feature.cc
diff --git a/chrome/common/extensions/permission_feature.cc b/chrome/common/extensions/permission_feature.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f0931926c22b51b7cf20e3bd4de4a679feadddf0
--- /dev/null
+++ b/chrome/common/extensions/permission_feature.cc
@@ -0,0 +1,33 @@
+// 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/common/extensions/permission_feature.h"
+
+#include "chrome/common/extensions/extension_permission_set.h"
+
+namespace extensions {
+
+PermissionFeature::PermissionFeature() {
+}
+
+PermissionFeature::~PermissionFeature() {
+}
+
+Feature::Availability PermissionFeature::IsAvailableToContext(
+    const Extension* extension,
+    Feature::Context context,
+    Feature::Platform platform) const {
+  Availability availability = Feature::IsAvailableToContext(extension,
+                                                            context,
+                                                            platform);
+  if (availability != IS_AVAILABLE)
+    return availability;
+
+  if (!extension->HasAPIPermission(name()))
+    return NOT_PRESENT;
+
+  return IS_AVAILABLE;
+}
+
+}  // namespace