Re-land "Fix glGetIntegerv(GL_TEXTURE_BINDING_EXTERNAL_OES, ...)"

BUG=angleproject:1332

Change-Id: Ie970466c4528cb80b2363d0c0683da2d9c23c4f4
Reviewed-on: https://chromium-review.googlesource.com/392267
Commit-Queue: John Bauman <jbauman@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/ContextState.cpp b/src/libANGLE/ContextState.cpp
index ef9b234..56f8d99 100644
--- a/src/libANGLE/ContextState.cpp
+++ b/src/libANGLE/ContextState.cpp
@@ -278,6 +278,14 @@
             *type      = GL_INT;
             *numParams = 1;
             return true;
+        case GL_TEXTURE_BINDING_EXTERNAL_OES:
+            if (!getExtensions().eglStreamConsumerExternal && !getExtensions().eglImageExternal)
+            {
+                return false;
+            }
+            *type      = GL_INT;
+            *numParams = 1;
+            return true;
     }
 
     if (getExtensions().debug)