Add an API for hosted apps to check their install and running states.

chrome/common/extensions/extension_constants.h

Index: chrome/common/extensions/extension_constants.h
diff --git a/chrome/common/extensions/extension_constants.h b/chrome/common/extensions/extension_constants.h
index 580ed7581abc570d052a101b5d51dde83cd14861..93a76ac94f290869d2b8862b55e99ae3d00e2cd6 100644
--- a/chrome/common/extensions/extension_constants.h
+++ b/chrome/common/extensions/extension_constants.h
@@ -237,6 +237,15 @@ namespace extension_misc {
     UNLOAD_REASON_TERMINATE,  // Extension has terminated.
   };
 
+  // The states that an app can be in, as reported by chrome.app.installState
+  // and chrome.app.runningState.
+  extern const char kAppStateNotInstalled[];
+  extern const char kAppStateInstalled[];
+  extern const char kAppStateDisabled[];
+  extern const char kAppStateRunning[];
+  extern const char kAppStateCannotRun[];
+  extern const char kAppStateReadyToRun[];
+
   // Error indicating that the app notifications API is not accessible by split
   // mode extensions in incognito windows.
   extern const char kAppNotificationsIncognitoError[];