ES31: Add PROGRAM_SEPARABLE to ProgramParameter and GetProgram

BUG=angleproject:1939
TEST=angle_end2end_tests

Change-Id: I97ad11360f7c015947a2c0cc7d4a47f994726834
Reviewed-on: https://chromium-review.googlesource.com/454264
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/renderer/gl/ProgramGL.cpp b/src/libANGLE/renderer/gl/ProgramGL.cpp
index acbed58..bc1c8f0 100644
--- a/src/libANGLE/renderer/gl/ProgramGL.cpp
+++ b/src/libANGLE/renderer/gl/ProgramGL.cpp
@@ -111,6 +111,11 @@
     }
 }
 
+void ProgramGL::setSeparable(bool separable)
+{
+    mFunctions->programParameteri(mProgramID, GL_PROGRAM_SEPARABLE, separable ? GL_TRUE : GL_FALSE);
+}
+
 LinkResult ProgramGL::link(ContextImpl *contextImpl,
                            const gl::VaryingPacking &packing,
                            gl::InfoLog &infoLog)