Move permission warning message handling from PermissionSet to PermissionMessageProvider.

chrome/common/extensions/permissions/app_permission_message_provider.cc

+// 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.
+
+#include "chrome/common/extensions/permissions/app_permission_message_provider.h"
+
+#include "chrome/common/extensions/permissions/permission_set.h"
+#include "extensions/common/permissions/permission_message.h"
+
+namespace extensions {
+
+AppPermissionMessageProvider::AppPermissionMessageProvider() {
+}
+
+AppPermissionMessageProvider::~AppPermissionMessageProvider() {
+}
+
+std::set<PermissionMessage>
+AppPermissionMessageProvider::GetHostPermissionMessages(

[Matt Perry, 2013/10/16 20:07:04]

It seems like these 2 special cases are the only reason you have multiple
message providers. Wouldn't it be simpler to just have 1 provider, and pass in
the manifest_type to these 2 methods?

[Yoyo Zhou, 2013/10/17 19:45:52]

Ok. I thought this was going to be more useful than it turned out to be. Changed
back to a single message provider.

(This makes a bunch of the other comments obsolete.)

+    const PermissionSet* permissions) const {
+  // Since platform apps always use isolated storage, they can't (silently)
+  // access user data on other domains, so there's no need to prompt.
+  // Note: this must remain consistent with HasLessHostPrivilegesThan.
+  // See crbug.com/255229.
+  std::set<PermissionMessage> messages;
+  return messages;
+}
+
+bool AppPermissionMessageProvider::IsHostPrivilegeIncrease(
+    const PermissionSet* old_permissions,
+    const PermissionSet* new_permissions) const {
+  // Platform apps host permission changes do not count as privilege increases.
+  // Note: this must remain consistent with GetHostPermissionMessages.
+  return false;
+}
+
+}  // namespace extensions