New link rel=prerender api, using WebKit::WebPrerenderingPlatform

chrome/browser/prerender/prerender_contents.cc

Index: chrome/browser/prerender/prerender_contents.cc
diff --git a/chrome/browser/prerender/prerender_contents.cc b/chrome/browser/prerender/prerender_contents.cc
index 098a67a74cb737c1920b8e06b86768543ec1dc75..5aab1c38b83ba3fb5d48eb9acc44612f3b23bef4 100644
--- a/chrome/browser/prerender/prerender_contents.cc
+++ b/chrome/browser/prerender/prerender_contents.cc
@@ -96,15 +96,6 @@ class PrerenderContentsFactoryImpl : public PrerenderContents::Factory {
   }
 };
 
-PrerenderContents::PendingPrerenderData::PendingPrerenderData(
-    Origin origin,
-    const GURL& url,
-    const content::Referrer& referrer)
-    : origin(origin),
-      url(url),
-      referrer(referrer) {
-}
-
 // TabContentsDelegateImpl -----------------------------------------------------
 
 class PrerenderContents::TabContentsDelegateImpl
@@ -197,11 +188,10 @@ class PrerenderContents::TabContentsDelegateImpl
   PrerenderContents* prerender_contents_;
 };
 
-void PrerenderContents::AddPendingPrerender(Origin origin,
-                                            const GURL& url,
+void PrerenderContents::AddPendingPrerender(const GURL& url,

[dominich, 2012/04/29 18:52:55]

I was worried about the loss of Origin here, but it's absolutely valid that you
can't have pending Omnibox prerenders. However, with other prerender origins
potentially coming down the pike it might be premature to remove it.

[gavinp, 2012/04/30 11:43:16]

I'll ping Timo, who's writing the history navigator.  Otherwise I can't think of
any other origins that would require this delay.  Can you?

[dominich, 2012/04/30 15:52:05]

None that are in active development, and it would be reasonably trivial to add
it back if necessary. I agree that the reduction in API complexity given the
current state of the implementation is worth it.

                                             const content::Referrer& referrer) {
   pending_prerender_list_.push_back(

[dominich, 2012/04/29 18:52:55]

nit: this line should be merged with the one below

[gavinp, 2012/04/30 11:43:16]

Done.

-      PendingPrerenderData(origin, url, referrer));
+      PendingPrerenderData(url, referrer));
 }
 
 bool PrerenderContents::IsPendingEntry(const GURL& url) const {
@@ -209,7 +199,7 @@ bool PrerenderContents::IsPendingEntry(const GURL& url) const {
            pending_prerender_list_.begin();
        it != pending_prerender_list_.end();
        ++it) {
-    if (it->url == url)
+    if (it->first == url)
       return true;
   }
   return false;
@@ -221,11 +211,11 @@ void PrerenderContents::StartPendingPrerenders() {
   for (PendingPrerenderList::iterator it = pending_prerender_list.begin();
        it != pending_prerender_list.end();
        ++it) {
-    prerender_manager_->AddPrerender(it->origin,
-                                     std::make_pair(child_id_, route_id_),
-                                     it->url,
-                                     it->referrer,
-                                     NULL);
+    RenderViewHost* render_view_host = RenderViewHost::FromID(child_id_,
+                                                              route_id_);
+    prerender_manager_->AddPrerenderFromLinkRelPrerender(

[dominich, 2012/04/29 18:52:55]

as above, this assumption makes me nervous.

[gavinp, 2012/04/30 11:43:16]

I think it's easy enough to add back if we need to.

+        child_id_, route_id_, it->first, it->second, size_,

[dominich, 2012/04/29 18:52:55]

is it possible that the WebView size has changed since the pending prerender was
added? Maybe get the size again from the RenderViewHost here?

[gavinp, 2012/04/30 11:43:16]

I believe that the prerender can't change size while it's not visible and
prerendering, but mmenke will know better.  It would be a shame if it could,
since then in this case we'd be back to using the less reliable sizes from the
RenderViewHost in the delayed prerendering case.

[dominich, 2012/04/30 15:52:05]

It sounds like we already have an issue that we might prerender at one size and
then resize on swap. In which case this should work the same as the existing
code, which is reasonable.

[mmenke, 2012/04/30 18:35:22]

It's currently not possible for a hidden WebView to be resized, but I would be
happier using the size passed along with the prerender request, rather than
depend on that.

+        render_view_host->GetSessionStorageNamespace());
   }
 }
 
@@ -267,17 +257,20 @@ PrerenderContents::Factory* PrerenderContents::CreateFactory() {
 }
 
 void PrerenderContents::StartPrerendering(
-    const RenderViewHost* source_render_view_host,
+    int creator_child_id,
+    const gfx::Size& size,
     content::SessionStorageNamespace* session_storage_namespace) {
   DCHECK(profile_ != NULL);
   DCHECK(!prerendering_has_started_);
   DCHECK(prerender_contents_.get() == NULL);
+  DCHECK_EQ(-1, creator_child_id_);
+  DCHECK(size_.IsEmpty());
+
+  creator_child_id_ = creator_child_id;
+  size_ = size;
 
   prerendering_has_started_ = true;
-  DCHECK(creator_child_id_ == -1);
-  DCHECK(alias_urls_.size() == 1);
-  if (source_render_view_host)
-    creator_child_id_ = source_render_view_host->GetProcess()->GetID();
+  DCHECK_EQ(1U, alias_urls_.size());
   InformRenderProcessAboutPrerender(prerender_url_, true,
                                     creator_child_id_);
 
@@ -285,16 +278,8 @@ void PrerenderContents::StartPrerendering(
   prerender_contents_.reset(new TabContentsWrapper(new_contents));
   content::WebContentsObserver::Observe(new_contents);
 
-  gfx::Rect tab_bounds = prerender_manager_->config().default_tab_bounds;
-  if (source_render_view_host) {
-    DCHECK(source_render_view_host->GetView() != NULL);
-    WebContents* source_wc =
-        source_render_view_host->GetDelegate()->GetAsWebContents();
-    if (source_wc) {
-      // Set the size of the new TC to that of the old TC.
-      source_wc->GetView()->GetContainerBounds(&tab_bounds);
-    }
-  } else {
+  if (size_.IsEmpty()) {

[dominich, 2012/04/29 18:52:55]

will this ever happen now the size is coming from the WebView directly?

[gavinp, 2012/04/30 11:43:16]

Yes.  Omnibox prerendering is probably the biggest cause.

+    size_ = prerender_manager_->config().default_tab_bounds.size();
 #if !defined(OS_ANDROID)
     // Try to get the active tab of the active browser and use that for tab
     // bounds. If the browser has never been active, we will fail to get a size
@@ -303,12 +288,14 @@ void PrerenderContents::StartPrerendering(
     // This code is unneeded on Android as we do not have a Browser object so we
     // can't get the size, and |default_tab_bounds| will be set to the right
     // value.
-    Browser* active_browser = BrowserList::GetLastActiveWithProfile(profile_);
-    if (active_browser) {
+    if (Browser* active_browser =
+            BrowserList::GetLastActiveWithProfile(profile_)) {
       WebContents* active_web_contents = active_browser->GetWebContentsAt(
           active_browser->active_index());
+      gfx::Rect container_bounds;
       if (active_web_contents)
-        active_web_contents->GetView()->GetContainerBounds(&tab_bounds);
+        active_web_contents->GetView()->GetContainerBounds(&container_bounds);
+      size_ = container_bounds.size();
     }
 #endif  // !defined(OS_ANDROID)
   }
@@ -317,8 +304,7 @@ void PrerenderContents::StartPrerendering(
   new_contents->SetDelegate(tab_contents_delegate_.get());
 
   // Set the size of the prerender WebContents.
-  prerender_contents_->web_contents()->GetView()->SizeContents(
-      tab_bounds.size());
+  prerender_contents_->web_contents()->GetView()->SizeContents(size_);
 
   // Register as an observer of the RenderViewHost so we get messages.
   render_view_host_observer_.reset(