Add PrerenderResourceHandler and hook it into the ResourceDispatcherHost....

chrome/browser/renderer_host/resource_dispatcher_host.cc

Index: chrome/browser/renderer_host/resource_dispatcher_host.cc
diff --git a/chrome/browser/renderer_host/resource_dispatcher_host.cc b/chrome/browser/renderer_host/resource_dispatcher_host.cc
index 2515b3b0e7570387a90e74d0869516bb09f41046..d5bf2463c9b8265a6f02238821df7fad3ff880ed 100644
--- a/chrome/browser/renderer_host/resource_dispatcher_host.cc
+++ b/chrome/browser/renderer_host/resource_dispatcher_host.cc
@@ -31,6 +31,7 @@
 #include "chrome/browser/net/chrome_url_request_context.h"
 #include "chrome/browser/net/url_request_tracking.h"
 #include "chrome/browser/plugin_service.h"
+#include "chrome/browser/prerender/prerender_resource_handler.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_host/async_resource_handler.h"
 #include "chrome/browser/renderer_host/buffered_resource_handler.h"
@@ -443,6 +444,16 @@ void ResourceDispatcherHost::BeginRequest(
     upload_size = request_data.upload_data->GetContentLength();
   }
 
+  // Install a PrerenderResourceHandler if the requested URL could
+  // be prerendered. This should be in front of the [a]syncResourceHandler,
+  // but after the BufferedResourceHandler since it depends on the MIME
+  // sniffing capabilities in the BufferedResourceHandler.
+  if (context && context->prerender_manager() &&
+      PrerenderResourceHandler::CouldPrerender(request)) {
+    handler = new PrerenderResourceHandler(handler,
+                                           context->prerender_manager());

[gavinp, 2010/12/17 16:15:33]

An idea, not sure if it's the right thing: how about PreRenderResourceHandler
has a private constructor, and instead there's a static method taking handler
and returning an handler, which hides CouldPrerender's call?  Two wins: this
call site is more succinct, and the unit test can check that CouldPrerender is
good?

[cbentzel, 2010/12/17 16:23:21]

I'm not sure I understand what you are asking for - or more importantly, the
value of it.

It seems like this would simply to change to

if (context && context->prerender_manager()) {
  handler = PrerenderResourceHandler::MaybeCreate(handler, request,
context->prerender_manager());
}

Where MaybeCreate would also need to return the passed in handler if
CouldPrerender is false. It seems like that makes the behavior less explicit at
the call site, and it doesn't make it that much more succinct.

I could add a unit test explicitly for CouldPrerender if desired.

+  }
+
   // Install a CrossSiteResourceHandler if this request is coming from a
   // RenderViewHost with a pending cross-site request.  We only check this for
   // MAIN_FRAME requests. Unblock requests only come from a blocked page, do