Fix a renderer crash when dragging quickly over tab contents.

content/browser/web_contents/web_drag_dest_gtk.cc

Index: content/browser/web_contents/web_drag_dest_gtk.cc
diff --git a/content/browser/web_contents/web_drag_dest_gtk.cc b/content/browser/web_contents/web_drag_dest_gtk.cc
index 20093f4a79826cd414efcc955e46d42c5b673961..b8768001463bf9423360021dbc781a4294a6dd8a 100644
--- a/content/browser/web_contents/web_drag_dest_gtk.cc
+++ b/content/browser/web_contents/web_drag_dest_gtk.cc
@@ -91,7 +91,6 @@ void WebDragDestGtk::UpdateDragStatus(WebDragOperation operation) {
 
 void WebDragDestGtk::DragLeave() {
   GetRenderViewHost()->DragTargetDragLeave();
-
   if (delegate())
     delegate()->OnDragLeave();
 
@@ -270,6 +269,12 @@ void WebDragDestGtk::OnDragLeave(GtkWidget* sender, GdkDragContext* context,
   // as an enter.
   context_ = NULL;
 
+  // Sometimes we get a drag-leave event before getting a drag-data-received
+  // event. In that case, we don't want to bother the renderer with a
+  // DragLeave event.
+  if (data_requests_ != 0)
+    return;
+
   // When GTK sends us a drag-drop signal, it is shortly (and synchronously)
   // preceded by a drag-leave. The renderer doesn't like getting the signals
   // in this order so delay telling it about the drag-leave till we are sure