Implement WebPrescientNetworking to trigger preconnect from Blink

content/renderer/renderer_webkitplatformsupport_impl.h

Index: content/renderer/renderer_webkitplatformsupport_impl.h
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.h b/content/renderer/renderer_webkitplatformsupport_impl.h
index de19386b53e1830b4fd3acc6fc5d21396a0fea27..60f78f1df2389d3ffc7c3c083ede7114e408b158 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.h
+++ b/content/renderer/renderer_webkitplatformsupport_impl.h
@@ -12,6 +12,7 @@
 #include "content/common/webkitplatformsupport_impl.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebIDBFactory.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebPreconnectMotivation.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSharedWorkerRepository.h"
 
 namespace cc {
@@ -52,6 +53,9 @@ class CONTENT_EXPORT RendererWebKitPlatformSupportImpl
   virtual bool isLinkVisited(unsigned long long linkHash);
   virtual WebKit::WebMessagePortChannel* createMessagePortChannel();
   virtual void prefetchHostName(const WebKit::WebString&);
+  virtual void preconnect(const WebKit::WebURL& url,

[jam, 2013/05/01 14:58:11]

this method and the above (prefetchHostName) are just pass-throughs to the
embedder. it seems that coneptually they're related to, although I realize
aren't the same thing as, prerendering. can we put them on WebPrerendererClient?
that way we wouldn't have to change content for these chrome-specific features.
we can rename the interface to something more generic if needed

[kouhei (in TOK), 2013/05/02 10:15:25]

prefetchHostName was not a chrome specific feature (in WebKit days), but I think
preconnect is a chrome specific feature.

I agree that all these conceptually related prefetch methods (prefetchHostName,
preconnect, prerender) should be organlized.

I'll try if these would fit in WebPrerendererClient.

[kouhei (in TOK), 2013/05/07 09:16:12]

Updated the patch to use WebPrerenderingSupport instead of the platform API.

+                          WebKit::WebPreconnectMotivation motivation,
+                          uint32_t motivationVariationId);
   virtual void cacheMetadata(
       const WebKit::WebURL&, double, const char*, size_t);
   virtual WebKit::WebString defaultLocale();