Properly throw java exceptions from shouldOverrideUrlLoading

base/message_loop/message_loop.cc

Index: base/message_loop/message_loop.cc
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index 93b9d0a2ec44bcc64567d197996faad652a242ff..7207e881206d37e21449e25092c1fd6289a99498 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -717,6 +717,18 @@ void MessageLoopForUI::Start() {
   // No Histogram support for UI message loop as it is managed by Java side
   static_cast<MessagePumpForUI*>(pump_.get())->Start(this);
 }
+
+void MessageLoopForUI::StartForTesting(
+    base::android::JavaMessageHandlerFactory* factory,
+    WaitableEvent* test_done_event) {
+  // No Histogram support for UI message loop as it is managed by Java side
+  static_cast<MessagePumpForUI*>(pump_.get())
+      ->StartForTesting(this, factory, test_done_event);

[danakj, 2016/08/17 18:40:15]

Oh I missed this earlier, but you can't call "ForTesting" methods from methods
that are not in test targets, this will trigger presubmit warnings for future
people (and should be for you too?). It will need a different name.

But I'm getting confused. There's a call to MessagePumpForUI::StartForTesting
here, but also in the JavaHandlerThread::StartMessageLoop override? Are both
needed?

[gsennton, 2016/08/17 19:23:46]

Yeah, it's causing a presubmit warning for me (though it told me I could ignore
it if I knew what I was doing), changed to StartForUnitTest.
JavaHandlerThread::StartMessageLoop is calling
MessageLoopForUI::StartForTesting, i.e. the method here, not the one in
MessagePumpForUI. MessageLoopForUI is just the middle-man in this case.

+}
+
+void MessageLoopForUI::Abort() {
+  static_cast<MessagePumpForUI*>(pump_.get())->Abort();
+}
 #endif
 
 #if defined(OS_IOS)