Refine some public files in xwalk runtime.

The public files under xwalk/runtime/browser should be
located to the correct compiling path and the unused codes
related to Android port in the resource dispatcher host
delegation file should be removed. This fix is to refine
the corresponding files in xwalk runtime.

BUG=https://crosswalk-project.org/jira/browse/XWALK-620
Merge pull request #1244 from ShDavidliu/resource_dispatcher

Refine some public files in xwalk runtime.