arc-app-launcher: Minimal support for ARC app launcher.

components/arc/common/arc_host_messages.h

 // Copyright 2015 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.
 
 // Messages sent from the ARC instance to the host.
 // Multiply-included message file, hence no include guard.
 
+#include <string>
+#include <vector>
+
 #include "ipc/ipc_message_macros.h"
 
 #define IPC_MESSAGE_START ArcInstanceHostMsgStart
 
 IPC_MESSAGE_CONTROL0(ArcInstanceHostMsg_InstanceReady)
+
+// Sends a list of available ARC apps to Chrome. |labels|, |packages| and
+// |activities| must have the same size and contain non-empty strings. This
+// message is sent in response to ArcInstanceMsg_RefreshApps message from
+// Chrome to ARC and when ARC receives boot completed notification.
+IPC_MESSAGE_CONTROL3(ArcInstanceHostMsg_AppsRefreshed,
+                     std::vector<std::string>, /* labels */
+                     std::vector<std::string>, /* packages */
+                     std::vector<std::string> /* activities */)
+
+// Sends an icon of required |scale_factor| for specific ARC app. The app is
+// defined by |package| and |activity|. The icon content cannot be empty and
+// must match to |scale_factor| assuming 48x48 for SCALE_FACTOR_100P.
+// |scale_factor| is an enum defined at ui/base/layout.h. This message is sent
+// in response to ArcInstanceMsg_RequestIcon from Chrome to ARC.
+IPC_MESSAGE_CONTROL4(ArcInstanceHostMsg_AppIcon,
+                     std::string, /* package */
+                     std::string, /* activity */
+                     int,         /* scale_factor */
+                     std::vector<uint8_t> /* icon_png_data */)