Framework : Lockscreen - Customizable shortcuts

Forward port lockscreen shortcuts

Change-Id: Ic3b935df5c0da35f31373d96943e442dc39cf11b

Conflicts:
	core/java/android/provider/Settings.java
	packages/Keyguard/res/drawable-hdpi/ic_lockscreen_chrome_activated.png
	packages/Keyguard/res/drawable-hdpi/ic_lockscreen_chrome_normal.png
	packages/Keyguard/res/drawable-hdpi/ic_lockscreen_contacts_activated.png
	packages/Keyguard/res/drawable-hdpi/ic_lockscreen_contacts_normal.png
	packages/Keyguard/res/drawable-mdpi/ic_lockscreen_chrome_activated.png
	packages/Keyguard/res/drawable-mdpi/ic_lockscreen_chrome_normal.png
	packages/Keyguard/res/drawable-mdpi/ic_lockscreen_contacts_activated.png
	packages/Keyguard/res/drawable-mdpi/ic_lockscreen_contacts_normal.png
	packages/Keyguard/res/drawable-xhdpi/ic_lockscreen_chrome_activated.png
	packages/Keyguard/res/drawable-xhdpi/ic_lockscreen_chrome_normal.png
	packages/Keyguard/res/drawable-xhdpi/ic_lockscreen_contacts_activated.png
	packages/Keyguard/res/drawable-xhdpi/ic_lockscreen_contacts_normal.png