Fix a crash that happens if a tab is closed while

chrome/browser/tab_contents/web_drag_source.cc

Index: chrome/browser/tab_contents/web_drag_source.cc
diff --git a/chrome/browser/tab_contents/web_drag_source.cc b/chrome/browser/tab_contents/web_drag_source.cc
index d61f3ba2170919f4042b6d15b6bbcc92404e9415..8a9ce8bdd37c3f8be694141b4356eec15c548000 100644
--- a/chrome/browser/tab_contents/web_drag_source.cc
+++ b/chrome/browser/tab_contents/web_drag_source.cc
@@ -37,11 +37,6 @@ WebDragSource::WebDragSource(gfx::NativeWindow source_wnd,
     : BaseDragSource(),
       source_wnd_(source_wnd),
       render_view_host_(render_view_host) {
-  // In an effort to try to track down http://crbug.com/12524 we now CHECK
-  // when a NULL render_view_host is passed to us. I think this is what is
-  // happening but it is hard to tell since the minidump is not helpful in this
-  // case. At least we can then rule that out.
-  CHECK(render_view_host_);
 }
 
 void WebDragSource::OnDragSourceCancel() {