[NOT FOR REVIEW] extensions-wm: Add experimental extension API for window management.

chrome/browser/extensions/event_names.h

Index: chrome/browser/extensions/event_names.h
diff --git a/chrome/browser/extensions/event_names.h b/chrome/browser/extensions/event_names.h
index b8e6187fcdead8b6cb66017440f3efba9e8f8fd2..faf48a04805d067f409fe5b0ca47c90e9370ed19 100644
--- a/chrome/browser/extensions/event_names.h
+++ b/chrome/browser/extensions/event_names.h
@@ -76,6 +76,13 @@ extern const char kBluetoothOnPowerChanged[];
 // Push messaging.
 extern const char kOnPushMessage[];
 
+// Window Management.
+extern const char kWmOnWindowCreated[];
+extern const char kWmOnWindowClosed[];
+extern const char kWmOnWindowHidden[];
+extern const char kWmOnWindowShown[];
+extern const char kWmOnActiveWindowChanged[];
+
 }  // namespace event_names
 
 }  // namespace extensions