webkit: Adding missed WEBGL directive changes.
The websettings for webgl were not under compiler directive
added same.

Change-Id: Iac15c2084c746c1f7a65a7fab124357ea2a7ab6a
webkit: remove JNI dependency for webgl
Change-Id: I535741b086abf2f58f4bb02883a3d5194b92cfd5
Use combined depth and stencil buffers
Use combined depth and stencil buffers when both are requested together.
When stencil and depth buffers are requested, create a packed buffer
instead of standalone buffers and attach it to both the DEPTH_ATTACHMENT
point as well as the STENCIL_ATTACHMENT point as per
OES_packed_depth_stencil extension to GLES2.

Change-Id: I88a8f6f2e7eaf7cc7c93d37c03a9f7777ccc2732
CRs-fixed: 45920