Revert "Remove the classic WebView from the build."

This reverts commit 3e9cdbe3fe00ef50eff256e7b5f4b6a1ae796ec5.

Change-Id: If0755d3e9b2846827e6e8b773ffe45f772c30275
Conditionalize libwebcore inclusion

Change-Id: I6c2d7e85a5c6000a7c3e2c69665a5cb74d8f980e