Force-use the pbuffer surface for destroy

Bug: 18518580

If CanvasContext is being destroyed() the Surface
is probably no longer valid as well, so make sure to
makeCurrent() to the pbuffer surface so that the
subsequent GL operations are not using an invalid
EGLSurface

Change-Id: Ica5d6a065841772c47e00ad65aa7894c7e27e043
1 file changed