add some methods for browser

Change-Id: Ic46ec8cf6cb7efbdf122ae83d0a58998692d69b1
not destroy miui home when "always-finish" switch on

N/A

Change-Id: I9b4fd99bd41f3512b75c8fa61efb4db4933ce5ce
Ref-Id: Iaeda8ec06d76b019fba6f2d58617943af7ca1d75
pick code from android 4.2, fix media scanner slow issue

MIUI-14439

Change-Id: I841b9d535314ce80281493a0699b6a5eeda02776
Ref-Id: I67a008073070dfb48c3fb5d3a522dfd00a5c3a3c