[misc-usecase][XWALK-679] Add a TC for Performance Timeline

- Add a Performance Timeline TC for calculate the time of access to resources on the page

Impacted tests(approved): new 1, update 0, delete 0
Unit test platform: [Android]
Unit test result summary: pass 1, fail 0, block 0
Merge pull request #248 from yunxliu/yunxliu/misc/performance_timeline

[misc-usecase][XWALK-679] Add a TC for calculate the time of access to resources on the page