Support CHROMIUM_path_rendering fragment operations

This brings two new APIs, BindFragmentInputLocation and
ProgramPathFragmentInputGen that together dictate how the
fragment shader varyings are used.

BUG=angleproject:1382

Change-Id: I4b52fd8a3555235a73aecd4f3dba2d500789cbb0
Reviewed-on: https://chromium-review.googlesource.com/357071
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Sami Väisänen <svaisanen@nvidia.com>
Commit-Queue: Sami Väisänen <svaisanen@nvidia.com>
diff --git a/src/libANGLE/renderer/d3d/ProgramD3D.cpp b/src/libANGLE/renderer/d3d/ProgramD3D.cpp
index d62bb72..c98c6f9 100644
--- a/src/libANGLE/renderer/d3d/ProgramD3D.cpp
+++ b/src/libANGLE/renderer/d3d/ProgramD3D.cpp
@@ -2309,4 +2309,13 @@
     *memberInfoOut = infoIter->second;
     return true;
 }
+
+void ProgramD3D::setPathFragmentInputGen(const std::string &inputName,
+                                         GLenum genMode,
+                                         GLint components,
+                                         const GLfloat *coeffs)
+{
+    UNREACHABLE();
+}
+
 }  // namespace rx