Implement QueryGL.

Passes all tests in:
 * dEQP-GLES3.functional.occlusion_query
 * angle_end2end_tests

BUG=angleproject:887

Change-Id: I643ab4c28cb545de9e7b0e1740e3fd8e2aa9d3d9
Reviewed-on: https://chromium-review.googlesource.com/302338
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tryjob-Request: Geoff Lang <geofflang@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/Query.cpp b/src/libANGLE/Query.cpp
index a402b73..e88ea2b 100644
--- a/src/libANGLE/Query.cpp
+++ b/src/libANGLE/Query.cpp
@@ -47,4 +47,13 @@
     return mQuery->getType();
 }
 
+rx::QueryImpl *Query::getImplementation()
+{
+    return mQuery;
+}
+
+const rx::QueryImpl *Query::getImplementation() const
+{
+    return mQuery;
+}
 }