[Android] Fix XWalk crash issue when exiting if remote debugging is enabled.

The root cause is that DevToolsHttpHandlerImpl::Stop has been called before
DevToolsClientHostImpl::InspectedContentsClosing. In that case, the thread
is released and message loop is set to null, so XWalk crashes.

The fix is to change the teardown sequence to destory view first, then shutdown
remote debugging server.

BUG=https://crosswalk-project.org/jira/browse/XWALK-312
Merge pull request #1115 from huningxin/remote-debugger-crash-fix

[Android] Fix XWalk crash issue when exiting if remote debugging is enab...
[Android] Add the test cases about onActivityResult.

This patch contains the test case about onActivityResult in shared
and embedded mode. It's for the runtime client.
Create a activity names "SecondActivity". In the runtime client activity,
it starts activity for result. In the second activity, it will create a new
intent, and transfer data to runtime client activity.

For embedded client test:
1. install XWalkRuntimeClientEmbeddedShell.apk
2. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientEmbeddedTest -v -f testOnActivityResult

For shared client test:
1. install XWalkRuntimeLib.apk
2. install XWalkRuntimeClientShell.apk
3. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientTest -v -f testOnActivityResult