[Android] Add test case for handling wtai uri

wtai is a standard w3c defined at http://www.w3.org/wiki/UriSchemes/wtai.

BUG=https://crosswalk-project.org/jira/browse/XWALK-321
Merge pull request #1174 from wang16/wtai_test

[Android] Add test case for handling wtai uri
[Android] Implement the native http authentication in xwalk runtime.

  Native http authentication has to be handled in xwalk runtime for Android
port. It is used to provide the xwalk login delegation and handle the http
authentication request. This fix is to provide the native xwalk login delegation
and set up the bridge between the native http authentication handler and corresponding
handler in runtime core java layer.

BUG=https://crosswalk-project.org/jira/browse/XWALK-159
Merge branch 'native_http_auth' of ssh://github.com/ShDavidliu/crosswalk into native_http_auth

Conflicts:
	runtime/android/java/src/org/xwalk/core/XWalkHttpAuthHandler.java
	runtime/android/java/src/org/xwalk/runtime/XWalkClientForTest.java
	runtime/app/android/xwalk_jni_registrar.cc
	runtime/browser/android/intercepted_request_data.h
	runtime/browser/android/intercepted_request_data_impl.cc
	runtime/browser/android/intercepted_request_data_impl.h
	runtime/browser/android/xwalk_content.h
	runtime/browser/android/xwalk_contents_client_bridge.cc
	runtime/browser/android/xwalk_contents_client_bridge.h
	runtime/browser/android/xwalk_contents_io_thread_client.h
	runtime/browser/android/xwalk_contents_io_thread_client_impl.cc
	runtime/browser/android/xwalk_contents_io_thread_client_impl.h
	runtime/browser/android/xwalk_http_auth_handler.cc
	runtime/browser/android/xwalk_http_auth_handler.h
	runtime/browser/android/xwalk_http_auth_handler_base.cc
	runtime/browser/android/xwalk_http_auth_handler_base.h
	runtime/browser/android/xwalk_login_delegate.cc
	runtime/browser/android/xwalk_login_delegate.h
	test/android/core/javatests/src/org/xwalk/core/xwview/test/NullContentsClient.java
	xwalk.gyp