Don't allow drop to panels (pop-ups) in ChromeOS.

chrome/browser/tab_contents/tab_contents.cc

Index: chrome/browser/tab_contents/tab_contents.cc
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 6cbf922c5d5f07b9f30cb5904e18a9ce234c1418..ddedca80834121e1dfbfd70310ebb3e071555bc4 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -1370,6 +1370,16 @@ void TabContents::OnCloseStarted() {
     tab_close_start_time_ = base::TimeTicks::Now();
 }
 
+bool TabContents::ShouldAcceptDragAndDrop() const {
+#if defined(OS_CHROMEOS)
+  // ChromeOS panels (pop-ups) do not take drag-n-drop.
+  // See http://crosbug.com/2413
+  return delegate() && !delegate()->IsPopup(const_cast<TabContents*>(this));
+#else
+  return true;
+#endif
+}
+
 TabContents* TabContents::CloneAndMakePhantom() {
   TabNavigation tab_nav;