Move permission warning message handling from PermissionSet to PermissionMessageProvider.

extensions/common/permissions/permission_message_provider.h

Index: extensions/common/permissions/permission_message_provider.h
diff --git a/extensions/common/permissions/permission_message_provider.h b/extensions/common/permissions/permission_message_provider.h
new file mode 100644
index 0000000000000000000000000000000000000000..7f682e3e5de37026462d2a4d3d70cf6bdf9ee515
--- /dev/null
+++ b/extensions/common/permissions/permission_message_provider.h
@@ -0,0 +1,58 @@
+// Copyright 2013 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.
+
+#ifndef EXTENSIONS_COMMON_PERMISSIONS_PERMISSION_MESSAGE_PROVIDER_H_
+#define EXTENSIONS_COMMON_PERMISSIONS_PERMISSION_MESSAGE_PROVIDER_H_
+
+#include <vector>
+
+#include "extensions/common/manifest.h"
+#include "extensions/common/permissions/permission_message.h"
+
+namespace extensions {
+
+class PermissionSet;
+
+// The PermissionMessageProvider interprets permissions, translating them
+// into warning messages to show to the user. It also determines whether
+// a new set of permissions entails showing new warning messages.
+class PermissionMessageProvider {
+ public:
+  PermissionMessageProvider() {}
+  virtual ~PermissionMessageProvider() {}
+
+  // Return the global permission message provider.
+  static const PermissionMessageProvider* Get();
+
+  // Gets the localized permission messages that represent this set.
+  // The set of permission messages shown varies by extension type.
+  virtual PermissionMessages GetPermissionMessages(
+      const PermissionSet* permissions,
+      Manifest::Type extension_type) const = 0;
+
+  // Gets the localized permission messages that represent this set (represented
+  // as strings). The set of permission messages shown varies by extension type.
+  virtual std::vector<string16> GetWarningMessages(
+      const PermissionSet* permissions,
+      Manifest::Type extension_type) const = 0;
+
+  // Gets the localized permission details for messages that represent this set
+  // (represented as strings). The set of permission messages shown varies by
+  // extension type.
+  virtual std::vector<string16> GetWarningMessagesDetails(
+      const PermissionSet* permissions,
+      Manifest::Type extension_type) const = 0;
+
+  // Returns true if |new_permissions| has a greater privilege level than
+  // |old_permissions|.
+  // Whether certain permissions are considered varies by extension type.
+  virtual bool IsPrivilegeIncrease(
+      const PermissionSet* old_permissions,
+      const PermissionSet* new_permissions,
+      Manifest::Type extension_type) const = 0;
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_PERMISSIONS_PERMISSION_MESSAGE_PROVIDER_H_