Properly throw java exceptions from shouldOverrideUrlLoading

base/android/java_handler_thread.h

Index: base/android/java_handler_thread.h
diff --git a/base/android/java_handler_thread.h b/base/android/java_handler_thread.h
index 1709ff4fce8c72bc9619cb87130dd06ceea62949..4b7f6307cf8280dbf49f1393072b5739687b407a 100644
--- a/base/android/java_handler_thread.h
+++ b/base/android/java_handler_thread.h
@@ -41,10 +41,15 @@ class BASE_EXPORT JavaHandlerThread {
                   const JavaParamRef<jobject>& obj,
                   jlong event);
 
+  virtual void StartMessageLoop();
+  virtual void StopMessageLoop();
+
   static bool RegisterBindings(JNIEnv* env);
 
- private:
+ protected:
   std::unique_ptr<base::MessageLoop> message_loop_;
+
+ private:
   ScopedJavaGlobalRef<jobject> java_thread_;
 };