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/Context.cpp b/src/libANGLE/Context.cpp
index 27020eb..e5f331d 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -145,7 +145,7 @@
     mResetStrategy = (notifyResets ? GL_LOSE_CONTEXT_ON_RESET_EXT : GL_NO_RESET_NOTIFICATION_EXT);
     mRobustAccess = robustAccess;
 
-    mCompiler = new Compiler(mRenderer->createCompiler(getData()));
+    mCompiler = new Compiler(mRenderer, getData());
 }
 
 Context::~Context()