Add SwappedOut to TabContentsDelegate to allow us to correctly delete TabContents.

When a page has an unload handler and we swap it out to make way for a Prerendered tab, we expect a call to the TabContentsDelegate when it closes. For cross-site navigations, we don't get that message as the RenderViewHost is swapped instead of closing.

BUG=103966
TEST=Enable prerender from omnibox (and ensure it's not disabled by field trial) and repeatedly navigate between cnn.com and telegraph.co.uk in the Omnibox. Note in the TaskManager that you do not see zombie Tab processes.


Review URL: http://codereview.chromium.org/8539027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110145 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 24 insertions, 3 deletions

diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index a9e8777..0601d03 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -9,6 +9,8 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
+#include "base/memory/weak_ptr.h"
+#include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
@@ -97,18 +99,29 @@ bool NeedMatchCompleteDummyForFinalStatus(FinalStatus final_status) {
 
 }  // namespace
 
-class PrerenderManager::OnCloseTabContentsDeleter : public TabContentsDelegate {
+class PrerenderManager::OnCloseTabContentsDeleter
+    : public TabContentsDelegate,
+      public base::SupportsWeakPtr<
+          PrerenderManager::OnCloseTabContentsDeleter> {
  public:
   OnCloseTabContentsDeleter(PrerenderManager* manager,
                             TabContentsWrapper* tab)
       : manager_(manager),
         tab_(tab) {
     tab_->tab_contents()->set_delegate(this);
+    MessageLoop::current()->PostDelayedTask(FROM_HERE,
+        base::Bind(&OnCloseTabContentsDeleter::ScheduleTabContentsForDeletion,
+                   this->AsWeakPtr(), true), kDeleteWithExtremePrejudiceTimeMs);
   }
 
   virtual void CloseContents(TabContents* source) OVERRIDE {
-    tab_->tab_contents()->set_delegate(NULL);
-    manager_->ScheduleDeleteOldTabContents(tab_.release(), this);
+    DCHECK_EQ(tab_->tab_contents(), source);
+    ScheduleTabContentsForDeletion(false);
+  }
+
+  virtual void SwappedOut(TabContents* source) OVERRIDE {
+    DCHECK_EQ(tab_->tab_contents(), source);
+    ScheduleTabContentsForDeletion(false);
   }
 
   virtual bool ShouldSuppressDialogs() OVERRIDE {
@@ -116,6 +129,14 @@ class PrerenderManager::OnCloseTabContentsDeleter : public TabContentsDelegate {
   }
 
  private:
+  static const int kDeleteWithExtremePrejudiceTimeMs = 3000;
+
+  void ScheduleTabContentsForDeletion(bool timeout) {
+    tab_->tab_contents()->set_delegate(NULL);
+    manager_->ScheduleDeleteOldTabContents(tab_.release(), this);
+    UMA_HISTOGRAM_BOOLEAN("Prerender.TabContentsDeleterTimeout", timeout);
+  }
+
   PrerenderManager* manager_;
   scoped_ptr<TabContentsWrapper> tab_;