Don't count host permission changes for v2 apps as a permission increase.

chrome/common/extensions/permissions/permission_set.h

Index: chrome/common/extensions/permissions/permission_set.h
diff --git a/chrome/common/extensions/permissions/permission_set.h b/chrome/common/extensions/permissions/permission_set.h
index 3de9287e8cafdf69a2b2bd0dd12ccd64b9f562be..efecbf48df68bc75dcb09fdacfc625239482475f 100644
--- a/chrome/common/extensions/permissions/permission_set.h
+++ b/chrome/common/extensions/permissions/permission_set.h
@@ -126,7 +126,9 @@ class PermissionSet
 
   // Returns true if |permissions| has a greater privilege level than this
   // permission set (e.g., this permission set has less permissions).
-  bool HasLessPrivilegesThan(const PermissionSet* permissions) const;
+  // Whether certain permissions are considered varies by extension type.
+  bool HasLessPrivilegesThan(const PermissionSet* permissions,
+                             Manifest::Type extension_type) const;
 
   const APIPermissionSet& apis() const { return apis_; }
 
@@ -166,17 +168,20 @@ class PermissionSet
   void InitEffectiveHosts();
 
   // Gets the permission messages for the API permissions.
-  std::set<PermissionMessage> GetSimplePermissionMessages() const;
+  std::set<PermissionMessage> GetAPIPermissionMessages() const;
+
+  // Gets the permission messages for the host permissions.
+  std::set<PermissionMessage> GetHostPermissionMessages(
+      Manifest::Type extension_type) const;
 
   // Returns true if |permissions| has an elevated API privilege level than
   // this set.
-  bool HasLessAPIPrivilegesThan(
-      const PermissionSet* permissions) const;
+  bool HasLessAPIPrivilegesThan(const PermissionSet* permissions) const;
 
   // Returns true if |permissions| has more host permissions compared to this

[miket_OOO, 2013/07/09 17:12:09]

Just a drive-by readability observation here. This method is much smarter than
this comment suggests. It's not a simple set comparison.

The comment is probably OK as-is if you think that every person using this
method will understand it's a high-level, semantic comparison. But if someone
tries something crazy like adding it into an equality test, it might lead to a
bad place.

[Yoyo Zhou, 2013/07/09 17:17:00]

Yeah, it can lead to surprising results, but I don't feel so bad since it's a
private method.

   // set.
-  bool HasLessHostPrivilegesThan(
-      const PermissionSet* permissions) const;
+  bool HasLessHostPrivilegesThan(const PermissionSet* permissions,
+                                 Manifest::Type extension_type) const;
 
   // Gets a list of the distinct hosts for displaying to the user.
   // NOTE: do not use this for comparing permissions, since this disgards some