Add enough ES 3.1 enums to support initializing the dEQP ES 3.1 tests.

BUG=angleproject:1442

Change-Id: Iece3efb272fdcbe004d4136129ba7bfe74ba5265
Reviewed-on: https://chromium-review.googlesource.com/405530
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/State.cpp b/src/libANGLE/State.cpp
index be4c102..208c50b 100644
--- a/src/libANGLE/State.cpp
+++ b/src/libANGLE/State.cpp
@@ -170,6 +170,10 @@
         mSamplerTextures[GL_TEXTURE_2D_ARRAY].resize(caps.maxCombinedTextureImageUnits);
         mSamplerTextures[GL_TEXTURE_3D].resize(caps.maxCombinedTextureImageUnits);
     }
+    if (clientVersion >= Version(3, 1))
+    {
+        mSamplerTextures[GL_TEXTURE_2D_MULTISAMPLE].resize(caps.maxCombinedTextureImageUnits);
+    }
     if (extensions.eglImageExternal || extensions.eglStreamConsumerExternal)
     {
         mSamplerTextures[GL_TEXTURE_EXTERNAL_OES].resize(caps.maxCombinedTextureImageUnits);
@@ -632,6 +636,9 @@
       case GL_DITHER:                        setDither(enabled);                break;
       case GL_PRIMITIVE_RESTART_FIXED_INDEX: setPrimitiveRestart(enabled);      break;
       case GL_RASTERIZER_DISCARD:            setRasterizerDiscard(enabled);     break;
+      case GL_SAMPLE_MASK:
+          UNIMPLEMENTED();
+          break;
       case GL_DEBUG_OUTPUT_SYNCHRONOUS:
           mDebug.setOutputSynchronous(enabled);
           break;