ES31: Enable shader storage buffer support for OpenGL backend

BUG=angleproject:1951
TEST=angle_end2end_tests:ShaderStorageBuffer

Change-Id: I1afc3cd005ad2e595c6ce937fc53e17423f8ec8b
Reviewed-on: https://chromium-review.googlesource.com/618132
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/gl/ProgramGL.cpp b/src/libANGLE/renderer/gl/ProgramGL.cpp
index 95770a2..1a54d19 100644
--- a/src/libANGLE/renderer/gl/ProgramGL.cpp
+++ b/src/libANGLE/renderer/gl/ProgramGL.cpp
@@ -508,7 +508,7 @@
     if (mUniformBlockRealLocationMap.empty())
     {
         mUniformBlockRealLocationMap.reserve(mState.getUniformBlocks().size());
-        for (const gl::UniformBlock &uniformBlock : mState.getUniformBlocks())
+        for (const gl::InterfaceBlock &uniformBlock : mState.getUniformBlocks())
         {
             const std::string &mappedNameWithIndex = uniformBlock.mappedNameWithArrayIndex();
             GLuint blockIndex =