arc: Support more types of notifications.

components/arc/common/bitmap.mojom

Index: components/arc/common/bitmap.mojom
diff --git a/mash/login/public/interfaces/login.mojom b/components/arc/common/bitmap.mojom
similarity index 58%
copy from mash/login/public/interfaces/login.mojom
copy to components/arc/common/bitmap.mojom
index 5a14cfa7a56b3d98b2e319a2a7ff3147de825c49..02d96647b6cf7833d42a0a8d7e84f92cfa1e9da4 100644
--- a/mash/login/public/interfaces/login.mojom
+++ b/components/arc/common/bitmap.mojom
@@ -2,9 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module mash.login.mojom;
+module arc.mojom;
 
-interface Login {
-  ShowLoginUI();
-  SwitchUser();
+struct ArcBitmap {
+  uint32 width;
+  uint32 height;
+  array<uint8> pixel_data;  // Must be ARGB_8888
 };