arc: Make ActivityName.activity_name nullable.

components/arc/common/intent_helper.mojom

 // Copyright 2016 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.
 //
 // Next MinVersion: 15
 
 module arc.mojom;
 
 import "scale_factor.mojom";
 
@@ skipping 47 matching lines @@
   [MinVersion=6] bool is_preferred;
   [MinVersion=11] string? action;  // e.g. "android.intent.action.VIEW"
   // RequestUrlHandlerList may fill |fallback_url| when it is called with an
   // intent: URL.
   [MinVersion=14] string? fallback_url;
 };
 
 // Describes an activity.
 struct ActivityName {
   string package_name;
-  string activity_name;
+  string? activity_name;  // may be null to indicate any activity within package
 };
 
 // Describes an icon for the activity.
 struct ActivityIcon {
   ActivityName activity;
   uint32 width;  // in px
   uint32 height;  // in px
   array<uint8> icon;  // in BGRA8888 format
 };
 
@@ skipping 74 matching lines @@
   // specified.  Data can be sent as extras by including a JSON map string which
   // will be automatically converted to a bundle accessible by the receiver.
   //
   // Note: Broadcasts can only be sent to whitelisted packages.  Packages can be
   // added to the whitelist in ArcBridgeService.java in the Android source.
   [MinVersion=1] SendBroadcast@1(string action,
                                  string package_name,
                                  string cls,
                                  string extras);
 };