Close the shell when all activities are destroyed.

shell/android/main.cc

Index: shell/android/main.cc
diff --git a/shell/android/main.cc b/shell/android/main.cc
index f94068422071deb41207106c73a04cd306724d2a..43001075aa4258aa230059ebd925bee59e3f5f13 100644
--- a/shell/android/main.cc
+++ b/shell/android/main.cc
@@ -142,6 +142,10 @@ void ConfigureAndroidServices(Context* context) {
       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();
@@ -341,6 +345,11 @@ static void BindShell(JNIEnv* env, jclass clazz, jint shell_handle) {
                                      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);
 }