Add an extension bubble explaining which extensions are in dev mode.

extensions/common/extension.h

 // Copyright (c) 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_EXTENSION_H_
 #define EXTENSIONS_COMMON_EXTENSION_H_
 
 #include <algorithm>
 #include <iosfwd>
 #include <map>
@@ skipping 241 matching lines @@
 
   // Returns true if the extension should be displayed in the extension
   // settings page (i.e. chrome://extensions).
   bool ShouldDisplayInExtensionSettings() const;
 
   // Returns true if the extension should not be shown anywhere. This is
   // mostly the same as the extension being a component extension, but also
   // includes non-component apps that are hidden from the app launcher and ntp.
   bool ShouldNotBeVisible() const;
 
+  // Returns true if the extension is considered a Developer Mode extension.
+  bool IsDevModeExtension() const;

[not at google - send to devlin, 2013/12/04 17:25:13]

I think this belongs in extension_util.h if anywhere. I'm not sure that the
model should care about this though, it's an interpretation of the data that
this is loaded in "developer mode". Could it go in one of the controller classes
instead?

[Finnur, 2013/12/05 23:55:56]

Sure. Done.

+
   // Get the manifest data associated with the key, or NULL if there is none.
   // Can only be called after InitValue is finished.
   ManifestData* GetManifestData(const std::string& key) const;
 
   // Sets |data| to be associated with the key. Takes ownership of |data|.
   // Can only be called before InitValue is finished. Not thread-safe;
   // all SetManifestData calls should be on only one thread.
   void SetManifestData(const std::string& key, ManifestData* data);
 
   // Accessors:
@@ skipping 259 matching lines @@
 
   UpdatedExtensionPermissionsInfo(
       const Extension* extension,
       const PermissionSet* permissions,
       Reason reason);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_EXTENSION_H_