Add an interm ShaderSh class.

This class logic will eventually move to the GL layer. Keep it
in the Renderer layer for now for refactoring purposes.

BUG=angleproject:1159

Change-Id: I91843099367f9a0293cc43ab98626bf79eb75ebf
Reviewed-on: https://chromium-review.googlesource.com/299875
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Shader.cpp b/src/libANGLE/Shader.cpp
index 1ddbfe3..73c5832 100644
--- a/src/libANGLE/Shader.cpp
+++ b/src/libANGLE/Shader.cpp
@@ -136,7 +136,7 @@
 
 void Shader::compile(Compiler *compiler)
 {
-    mCompiled = mShader->compile(compiler, mSource);
+    mCompiled = mShader->compile(compiler, mSource, 0);
 }
 
 void Shader::addRef()