Bug 795252 - Part 1: Refactore StkCommandParamsFactory. r=yoshi
Bug 795252 - Part 2: Refactore StkProactiveCmdHelper. r=yoshi.
Bug 795252 - Part 3: Modify marionette stk tests. r=yoshi
Bug 795252 - Part 4: Modify xpcshell STK tests. r=yoshi