Fix a crash that happens if a tab is closed while

chrome/browser/tab_contents/tab_contents_view.h

Index: chrome/browser/tab_contents/tab_contents_view.h
diff --git a/chrome/browser/tab_contents/tab_contents_view.h b/chrome/browser/tab_contents/tab_contents_view.h
index 6acbb302ce7bd981531e8cc75087c5115ab682bc..b8e949b5279be2f7c47f1b8eede9d0c0dfad1281 100644
--- a/chrome/browser/tab_contents/tab_contents_view.h
+++ b/chrome/browser/tab_contents/tab_contents_view.h
@@ -138,6 +138,14 @@ class TabContentsView : public RenderViewHostDelegate::View {
     return preferred_width_;
   }
 
+  // If we try to close the tab while a drag is in progress, we crash.  These
+  // methods allow the tab contents to determine if a drag is in progress and
+  // postpone the tab closing.
+  virtual bool IsDoingDrag() const {
+    return false;
+  }
+  virtual void CancelDragAndCloseTab() {}
+
  protected:
   TabContentsView() {}  // Abstract interface.