Close the shell when all activities are destroyed.

shell/android/main.cc

 // Copyright 2013 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.
 
 #include "shell/android/main.h"
 
 #include <stdio.h>
 
 #include "base/android/fifo_utils.h"
 #include "base/android/jni_android.h"
@@ skipping 124 matching lines @@
             new JavaApplicationLoader(java_application_registry, url)),
         GURL(url));
   }
 
   // By default, the authenticated_network_service is handled by the
   // authentication service.
   context->url_resolver()->AddURLMapping(
       GURL("mojo:authenticated_network_service"), GURL("mojo:authentication"));
 }
 
+void QuitShellMessageLoopCallback() {
+  base::MessageLoop::current()->QuitWhenIdle();
+}
+
 void QuitShellThread() {
   g_internal_data.Get().shell_thread->Join();
   g_internal_data.Get().shell_thread.reset();
   Java_ShellService_finishActivities(base::android::AttachCurrentThread());
   exit(0);
 }
 
 void MojoShellRunner::Run() {
   base::MessageLoop loop(mojo::common::MessagePumpMojo::Create());
   g_internal_data.Get().shell_task_runner = loop.task_runner();
@@ skipping 179 matching lines @@
       FROM_HERE, base::Bind(&StartApplicationByURL, url));
 }
 
 static void BindShell(JNIEnv* env, jclass clazz, jint shell_handle) {
   g_internal_data.Get().shell_task_runner->PostTask(
       FROM_HERE,
       base::Bind(&BindShellImpl, base::Passed(mojo::ScopedMessagePipeHandle(
                                      mojo::MessagePipeHandle(shell_handle)))));
 }
 
+static void QuitShell(JNIEnv* env, jclass jcaller) {
+  g_internal_data.Get().shell_task_runner->PostTask(
+      FROM_HERE, base::Bind(&QuitShellMessageLoopCallback));

[qsr, 2015/12/09 12:00:01]

Why not use MessageLoop::QuitClosure() instead?

[etiennej, 2015/12/09 12:09:26]

Done.

+}
+
 bool RegisterShellService(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace shell