Implement primitive restart boolean query.

We have support for primitive restart in the GL renderer, but we
didn't complete support for the state query.

BUG=angleproject:1101

Change-Id: I4c6ad10642f7de1d09718c4582f1037782cced58
Reviewed-on: https://chromium-review.googlesource.com/309151
Tryjob-Request: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@google.com>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index 5d7b22c..5fa30b2 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -1270,6 +1270,7 @@
 
       case GL_TRANSFORM_FEEDBACK_ACTIVE:
       case GL_TRANSFORM_FEEDBACK_PAUSED:
+      case GL_PRIMITIVE_RESTART_FIXED_INDEX:
         {
             *type = GL_BOOL;
             *numParams = 1;