Helper functions for tracking stale TabContentsDelegate's.

content/browser/tab_contents/tab_contents.cc

Index: content/browser/tab_contents/tab_contents.cc
diff --git a/content/browser/tab_contents/tab_contents.cc b/content/browser/tab_contents/tab_contents.cc
index cc805054f208b971cb56e8f7554f03984c3bdc26..43a46f78fde0f7999694d8b0f522dd349e986aed 100644
--- a/content/browser/tab_contents/tab_contents.cc
+++ b/content/browser/tab_contents/tab_contents.cc
@@ -623,6 +623,19 @@ void TabContents::AddNewContents(TabContents* new_contents,
                             user_gesture);
 }
 
+void TabContents::set_delegate(TabContentsDelegate* delegate) {
+  if (delegate == delegate_)
+    return;
+
+  if (delegate_)
+    delegate_->Detach(this);
+
+  delegate_ = delegate;
+
+  if (delegate_)
+    delegate_->Attach(this);
+}
+
 gfx::NativeView TabContents::GetContentNativeView() const {
   return view_->GetContentNativeView();
 }