Two minor tweaks to prerender:

. Don't attempt to swap if the TabContentsWrapper has no delegate.
. Reset the delegate before returning the TabContents.

I'm doing this as we have crash reports of a TabContentsDelegate being
deleted before the TabContents.

BUG=85247
TEST=none
R=cbentzel@chromium.org

Review URL: http://codereview.chromium.org/7246012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90256 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 13 insertions, 5 deletions

diff --git a/chrome/browser/prerender/prerender_contents.cc b/chrome/browser/prerender/prerender_contents.cc
index 3247aae..ae72b91 100644
--- a/chrome/browser/prerender/prerender_contents.cc
+++ b/chrome/browser/prerender/prerender_contents.cc
@@ -537,6 +537,7 @@ void PrerenderContents::DestroyWhenUsingTooManyResources() {
 }
 
 TabContentsWrapper* PrerenderContents::ReleasePrerenderContents() {
+  prerender_contents_->tab_contents()->set_delegate(NULL);
   render_view_host_observer_.reset();
   prerender_contents_->download_tab_helper()->set_delegate(NULL);
   TabContentsObserver::Observe(NULL);
diff --git a/chrome/browser/prerender/prerender_observer.cc b/chrome/browser/prerender/prerender_observer.cc
index 8f286aa..eb5e257 100644
--- a/chrome/browser/prerender/prerender_observer.cc
+++ b/chrome/browser/prerender/prerender_observer.cc
@@ -7,13 +7,15 @@
 #include "base/time.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/common/view_messages.h"
 
 namespace prerender {
 
-PrerenderObserver::PrerenderObserver(TabContents* tab_contents)
-    : TabContentsObserver(tab_contents),
+PrerenderObserver::PrerenderObserver(TabContentsWrapper* tab)
+    : TabContentsObserver(tab->tab_contents()),
+      tab_(tab),
       pplt_load_start_() {
 }
 
@@ -22,6 +24,8 @@ PrerenderObserver::~PrerenderObserver() {
 
 void PrerenderObserver::ProvisionalChangeToMainFrameUrl(const GURL& url,
                                                         bool has_opener_set) {
+  if (!tab_->delegate())
+    return;  // PrerenderManager needs a delegate to handle the swap.
   PrerenderManager* prerender_manager = MaybeGetPrerenderManager();
   if (!prerender_manager)
     return;
diff --git a/chrome/browser/prerender/prerender_observer.h b/chrome/browser/prerender/prerender_observer.h
index 324644c..9f8526a 100644
--- a/chrome/browser/prerender/prerender_observer.h
+++ b/chrome/browser/prerender/prerender_observer.h
@@ -9,7 +9,7 @@
 
 #include "base/time.h"
 
-class TabContents;
+class TabContentsWrapper;
 class GURL;
 
 namespace prerender {
@@ -21,7 +21,7 @@ class PrerenderManager;
 // to compare PLT's with prerendering enabled and disabled.
 class PrerenderObserver : public TabContentsObserver {
  public:
-  explicit PrerenderObserver(TabContents* tab_contents);
+  explicit PrerenderObserver(TabContentsWrapper* tab);
   virtual ~PrerenderObserver();
 
   // TabContentsObserver implementation.
@@ -51,6 +51,9 @@ class PrerenderObserver : public TabContentsObserver {
   // Returns whether the TabContents being observed is currently prerendering.
   bool IsPrerendering();
 
+  // TabContentsWrapper we're created for.
+  TabContentsWrapper* tab_;
+
   // System time at which the current load was started for the purpose of
   // the perceived page load time (PPLT).
   base::TimeTicks pplt_load_start_;
diff --git a/chrome/browser/ui/tab_contents/tab_contents_wrapper.cc b/chrome/browser/ui/tab_contents/tab_contents_wrapper.cc
index 18fc132..4ee881b 100644
--- a/chrome/browser/ui/tab_contents/tab_contents_wrapper.cc
+++ b/chrome/browser/ui/tab_contents/tab_contents_wrapper.cc
@@ -137,7 +137,7 @@ TabContentsWrapper::TabContentsWrapper(TabContents* contents)
   external_protocol_observer_.reset(new ExternalProtocolObserver(contents));
   file_select_observer_.reset(new FileSelectObserver(contents));
   plugin_observer_.reset(new PluginObserver(this));
-  prerender_observer_.reset(new prerender::PrerenderObserver(contents));
+  prerender_observer_.reset(new prerender::PrerenderObserver(this));
   print_preview_.reset(new printing::PrintPreviewMessageHandler(contents));
   webnavigation_observer_.reset(
       new ExtensionWebNavigationTabObserver(contents));