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

chrome/common/extensions/extension_constants.cc

Index: chrome/common/extensions/extension_constants.cc
diff --git a/chrome/common/extensions/extension_constants.cc b/chrome/common/extensions/extension_constants.cc
index e3de26713d898b45b00d0ea5b42fa9d66b871664..9212ec25d751167f2093fcc219ba7b1fe627ed7c 100644
--- a/chrome/common/extensions/extension_constants.cc
+++ b/chrome/common/extensions/extension_constants.cc
@@ -112,6 +112,14 @@ const char kAccessExtensionPath[] =
     "/usr/share/chromeos-assets/accessibility/extensions";
 const char kChromeVoxDirectoryName[] = "access_chromevox";
 #endif
+
+const char kAppStateNotInstalled[] = "not_installed";
+const char kAppStateInstalled[] = "installed";
+const char kAppStateDisabled[] = "disabled";
+const char kAppStateRunning[] = "running";
+const char kAppStateCannotRun[] = "cannot_run";
+const char kAppStateReadyToRun[] = "ready_to_run";
+
 const char kAppNotificationsIncognitoError[] =
     "This API is not accessible by 'split' mode "
     "extensions in incognito windows.";