Hook prerender into non-CURRENT_TAB dispositions.

chrome/browser/ui/browser_navigator.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/browser_navigator.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
@@ skipping 595 matching lines @@
       params->target_contents = CreateTargetContents(*params, url);
 
       // This function takes ownership of |params->target_contents| until it
       // is added to a TabStripModel.
       target_contents_owner.TakeOwnership();
     } else {
       // ... otherwise if we're loading in the current tab, the target is the
       // same as the source.
       DCHECK(params->source_contents);
       params->target_contents = params->source_contents;
-      DCHECK(params->target_contents);
-      // Prerender expects |params->target_contents| to be attached to a browser
-      // window, so only call for CURRENT_TAB navigations. (Others are currently
-      // unsupported because of session storage namespaces anyway.)
-      // Notice that this includes middle-clicking, since middle clicking
-      // translates into a chrome::Navigate call with no URL followed by a
-      // CURRENT_TAB navigation.
-      // TODO(tburkard): We can actually swap in in non-CURRENT_TAB cases, as
-      // long as the WebContents we swap into is part of a TabStrip model.
-      // Therefore, we should swap in regardless of CURRENT_TAB, and instead,
-      // check in the swapin function whether the WebContents is not in a
-      // TabStrip model, in which case we must not swap in.
-      swapped_in_prerender = SwapInPrerender(url, params);
     }
 
+    // Note: at this point, if |params->disposition| is not CURRENT_TAB,
+    // |params->target_contents| has not been attached to a Browser yet. (That
+    // happens later in this function.) However, in that case, the
+    // sessionStorage namespace could not match, so prerender will use the
+    // asynchronous codepath and still swap.
+    DCHECK(params->target_contents);
+    swapped_in_prerender = SwapInPrerender(url, params);
+
     if (user_initiated)
       params->target_contents->UserGestureDone();
 
     if (!swapped_in_prerender) {
       // Try to handle non-navigational URLs that popup dialogs and such, these
       // should not actually navigate.
       if (!HandleNonNavigationAboutURL(url)) {
         // Perform the actual navigation, tracking whether it came from the
         // renderer.
 
@@ skipping 123 matching lines @@
   bool reverse_on_redirect = false;
   content::BrowserURLHandler::GetInstance()->RewriteURLIfNecessary(
       &rewritten_url, browser_context, &reverse_on_redirect);
 
   // Some URLs are mapped to uber subpages. Do not allow them in incognito.
   return !(rewritten_url.scheme() == content::kChromeUIScheme &&
            rewritten_url.host() == chrome::kChromeUIUberHost);
 }
 
 }  // namespace chrome