Add support for eglCreatePbufferFromClientBuffer, taking as input a D3D share handle corresponding to the enum EGL_D3D_TEXTURE_2D_SHARE_HANDLE_ANGLE. No spec as of yet, but it does the obvious thing.

BUG=129
TEST=

Review URL: http://codereview.appspot.com/4325048

git-svn-id: https://angleproject.googlecode.com/svn/trunk@650 736b8ea6-26fd-11df-bfd4-992fa37f6226