[NoStatePrefetch] Do not send responses to renderer in prefetch mode.

third_party/WebKit/Source/web/WebDocument.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 119 matching lines @@
 bool WebDocument::isXHTMLDocument() const
 {
     return constUnwrap<Document>()->isXHTMLDocument();
 }
 
 bool WebDocument::isPluginDocument() const
 {
     return constUnwrap<Document>()->isPluginDocument();
 }
 
+bool WebDocument::isPrefetchOnly() const
+{
+    return constUnwrap<Document>()->isPrefetchOnly();

[clamy, 2016/08/25 22:34:59]

How is isPrefetchOnly set on the document? Is this only true for no-state
prefetch?

[mattcary, 2016/08/26 08:17:51]

Yes, only true for no-state prefetch currently. It's set from the
PrerenderContents on the browser via the render frame, see here:

https://cs.chromium.org/chromium/src/chrome/browser/prerender/prerender_conte...

Currently prerender_contents is only set to be prefetch via a command-line flag.
There is discussion that as the nostate prefetch experiment evolves, we may set
it conditionally based on the prerender origin. Regardless, it's the prerender
manager/prerender contents that controls isPrefetchOnly.

+}
+
 WebURL WebDocument::baseURL() const
 {
     return constUnwrap<Document>()->baseURL();
 }
 
 WebURL WebDocument::firstPartyForCookies() const
 {
     return constUnwrap<Document>()->firstPartyForCookies();
 }
 
@@ skipping 177 matching lines @@
     m_private = elem;
     return *this;
 }
 
 WebDocument::operator Document*() const
 {
     return toDocument(m_private.get());
 }
 
 } // namespace blink