Revert "Runtime enablement of WebGL"

not longer needed webgl is always on on 4.3

This reverts commit df8d4cbe4821845a32c35ad5e452003dd607d09e.

Conflicts:
	res/values/strings.xml
	res/xml-sw600dp/lab_preferences.xml
	res/xml/lab_preferences.xml
	src/com/android/browser/BrowserSettings.java
	src/com/android/browser/PreferenceKeys.java

Change-Id: Ib19ebbbda3e3015a7a48196211b0980ccf40dbe2