ES31: Enable atomic counter for GL backend

This simply translates the offset qualifier and synchronizes
the buffer binding state for GL translator and renderer.

BUG=angleproject:1729
TEST=angle_end2end_tests:AtomicCounterBufferTest31

Change-Id: Ib8424918478ae4c47049d5856ea20ef022f12913
Reviewed-on: https://chromium-review.googlesource.com/575913
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/common/utilities.cpp b/src/common/utilities.cpp
index d0db43e..156bbfb 100644
--- a/src/common/utilities.cpp
+++ b/src/common/utilities.cpp
@@ -711,7 +711,20 @@
       case GL_SAMPLER_2D_SHADOW:
       case GL_SAMPLER_2D_ARRAY_SHADOW:
       case GL_SAMPLER_CUBE_SHADOW:
-        return 6;
+      case GL_IMAGE_2D:
+      case GL_INT_IMAGE_2D:
+      case GL_UNSIGNED_INT_IMAGE_2D:
+      case GL_IMAGE_3D:
+      case GL_INT_IMAGE_3D:
+      case GL_UNSIGNED_INT_IMAGE_3D:
+      case GL_IMAGE_2D_ARRAY:
+      case GL_INT_IMAGE_2D_ARRAY:
+      case GL_UNSIGNED_INT_IMAGE_2D_ARRAY:
+      case GL_IMAGE_CUBE:
+      case GL_INT_IMAGE_CUBE:
+      case GL_UNSIGNED_INT_IMAGE_CUBE:
+      case GL_UNSIGNED_INT_ATOMIC_COUNTER:
+          return 6;
 
       default:
         UNREACHABLE();