Add support for READ_BUFFER and SAMPLER_BINDING queries

BUG=angleproject:1101
TEST=dEQP-GLES3.functional.state_query.integers.* (all pass)

Change-Id: I3a70335eeaef39822700ff639443a59849ed53fa
Reviewed-on: https://chromium-review.googlesource.com/329866
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index cd860d7..89c77a2 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -1459,6 +1459,8 @@
       case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
       case GL_COPY_READ_BUFFER_BINDING:
       case GL_COPY_WRITE_BUFFER_BINDING:
+      case GL_SAMPLER_BINDING:
+      case GL_READ_BUFFER:
       case GL_TEXTURE_BINDING_3D:
       case GL_TEXTURE_BINDING_2D_ARRAY:
       case GL_MAX_3D_TEXTURE_SIZE: