Remove CompilerImpl and merge code to gl::Compiler.

This class uses no Impl-specific code. We can also do a similar
code relocation for the gl::Shader class, but in several steps
because it is a bit more complex.

BUG=angleproject:1159

Change-Id: I4d3ce3253df0a2bdee1d98e46cfd4b999d86be6e
Reviewed-on: https://chromium-review.googlesource.com/299874
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/gl/RendererGL.cpp b/src/libANGLE/renderer/gl/RendererGL.cpp
index c17ec58..c1a12cb 100644
--- a/src/libANGLE/renderer/gl/RendererGL.cpp
+++ b/src/libANGLE/renderer/gl/RendererGL.cpp
@@ -237,9 +237,9 @@
     return gl::Error(GL_NO_ERROR);
 }
 
-CompilerImpl *RendererGL::createCompiler(const gl::Data &data)
+CompilerImpl *RendererGL::createCompiler()
 {
-    return new CompilerGL(data, mFunctions);
+    return new CompilerGL(mFunctions);
 }
 
 ShaderImpl *RendererGL::createShader(GLenum type)