Implement WebSettings.{get|set}TextSize via {get|set}TextZoom. DO NOT MERGE

TextSize is deprecated, so we wouldn't expect from WebViewProvider
implementations to re-implement it in some other way than Android WebView does
it. This also makes recently added TextSize.getValue method redundant.

Clean cherry pick: 1202d66f78fb24850b997e37f0ce3cb3b36e4bbf

Change-Id: Ib6aecb187f10ac3ec5d12cb839cb814ec0c564fe
2 files changed