add some methods for browser

Change-Id: I9a62120e9ff40a2c87f05fffa47e9be04502f952
not destroy miui home when "always-finish" switch on

N/A

Change-Id: Ifbce9f4c2db13c0ed5c9b926213a62afc1ee3c97
Ref-Id: Iaeda8ec06d76b019fba6f2d58617943af7ca1d75
pick code from android 4.2, fix media scanner slow issue

MIUI-14439

Change-Id: I055e97e61055f23728a70559ad34d86f27b41442
Ref-Id: I67a008073070dfb48c3fb5d3a522dfd00a5c3a3c