ES31: Support bindImageTexture on Texture2D for compute shaders on D3D

BUG=angleproject:1987
TEST=angle_end2end_tests

Change-Id: I3b0afb441a41dbd7f204b1d1bba7884c8d203ce1
Reviewed-on: https://chromium-review.googlesource.com/749004
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/CollectVariables.cpp b/src/compiler/translator/CollectVariables.cpp
index b7136f2..f97dd3d 100644
--- a/src/compiler/translator/CollectVariables.cpp
+++ b/src/compiler/translator/CollectVariables.cpp
@@ -697,6 +697,8 @@
     uniform.binding  = variable.getType().getLayoutQualifier().binding;
     uniform.location = variable.getType().getLayoutQualifier().location;
     uniform.offset   = variable.getType().getLayoutQualifier().offset;
+    uniform.readonly  = variable.getType().getMemoryQualifier().readonly;
+    uniform.writeonly = variable.getType().getMemoryQualifier().writeonly;
     return uniform;
 }