Refactors parts of gin:

gin/public/context_holder.h

Index: gin/public/context_holder.h
diff --git a/gin/public/context_holder.h b/gin/public/context_holder.h
index f8f0c4727a5f6a66703f88d162f52833b0a28eed..afbcf23d73933c6daf4756c535f0340ea93cdab3 100644
--- a/gin/public/context_holder.h
+++ b/gin/public/context_holder.h
@@ -25,9 +25,7 @@ enum ContextEmbedderDataFields {
 
 class PerContextData;
 
-// ContextHolder is a generic class for holding a v8::Context. Rather than
-// using ContextHolder directly, most code should use a subclass of
-// ContextHolder, such as Runner.
+// ContextHolder is a generic class for holding a v8::Context.
 class GIN_EXPORT ContextHolder {
  public:
   explicit ContextHolder(v8::Isolate* isolate);