android: Java-based launcher thread

base/test/android/java_handler_thread_for_testing.cc

 // 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.
 
 #include "base/test/android/java_handler_thread_for_testing.h"
 
 #include "base/message_loop/message_loop.h"
+#include "jni/JavaHandlerThreadTest_jni.h"
 
 namespace base {
 namespace android {
 
 base::android::ScopedJavaLocalRef<jobject>
 TestJavaMessageHandlerFactory::CreateMessageHandler(
     JNIEnv* env,
     base::MessagePump::Delegate* delegate,
     MessagePumpForUI* message_pump,
     WaitableEvent* test_done_event) {
   return TestSystemMessageHandlerLink::CreateTestSystemMessageHandler(
       env, delegate, message_pump, test_done_event);
 }
 
 JavaHandlerThreadForTesting::JavaHandlerThreadForTesting(
     const char* name,
     base::WaitableEvent* test_done_event)
     : JavaHandlerThread(name),
       message_handler_factory_(new TestJavaMessageHandlerFactory()),
       test_done_event_(test_done_event) {}
 
+JavaHandlerThreadForTesting::JavaHandlerThreadForTesting(
+    base::WaitableEvent* test_done_event)
+    : JavaHandlerThread(Java_JavaHandlerThreadTest_testAndGetJavaHandlerThread(
+          base::android::AttachCurrentThread())),
+      message_handler_factory_(new TestJavaMessageHandlerFactory()),
+      test_done_event_(test_done_event) {}
+
 JavaHandlerThreadForTesting::~JavaHandlerThreadForTesting() = default;
 
 void JavaHandlerThreadForTesting::StartMessageLoop() {
   static_cast<MessageLoopForUI*>(message_loop_.get())
-      ->StartForTesting(
-          message_handler_factory_.get(),
-          reinterpret_cast<base::WaitableEvent*>(test_done_event_));
+      ->StartForTesting(message_handler_factory_.get(), test_done_event_);
 }
 
 void JavaHandlerThreadForTesting::StopMessageLoop() {
   // Instead of calling MessageLoop::QuitWhenIdle here we call
   // MessageLoop::QuitNow. This is because QuitWhenIdle will have no effect on
   // the message loop after MessageLoop::Abort has been called (which should
   // have happened at this point).
   static_cast<MessageLoopForUI*>(message_loop_.get())->QuitNow();
   // The message loop must be destroyed on the thread it is attached to.
   message_loop_.reset();
 }
 
 }  // namespace base
 }  // namespace android