Add extra delegate method to mac unit test.

TBR=pinkerton

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20058 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/cocoa/tab_strip_controller_unittest.mm

@@ -26,6 +26,10 @@ class TestTabStripDelegate : public TabStripModelDelegate {
                                               const DockInfo& dock_info) {
     return NULL;
   }
+  virtual void ContinueDraggingDetachedTab(TabContents* contents,
+                                         const gfx::Rect& window_bounds,
+                                         const gfx::Rect& tab_bounds) {
+  }
   virtual int GetDragActions() const {
     return 0;
   }