WGL Pbuffer implementation.

BUG:angleproject:890

Change-Id: Id6e04117ddf7bde3ffb0d9e4cef6db3d07039a54
Reviewed-on: https://chromium-review.googlesource.com/261410
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/tests/end2end_tests/PbufferTest.cpp b/src/tests/end2end_tests/PbufferTest.cpp
index 72379cd..06f3f53 100644
--- a/src/tests/end2end_tests/PbufferTest.cpp
+++ b/src/tests/end2end_tests/PbufferTest.cpp
@@ -1,7 +1,7 @@
 #include "ANGLETest.h"
 
 // Use this to select which configurations (e.g. which renderer, which GLES major version) these tests should be run against.
-ANGLE_TYPED_TEST_CASE(PbufferTest, ES2_D3D9, ES2_D3D11);
+ANGLE_TYPED_TEST_CASE(PbufferTest, ES2_D3D9, ES2_D3D11, ES2_OPENGL);
 
 template<typename T>
 class PbufferTest : public ANGLETest