Fix "unreachable code" warnings (MSVC warning 4702) in chrome/browser/.

chrome/browser/ui/views/tabs/tab_drag_controller.cc

Index: chrome/browser/ui/views/tabs/tab_drag_controller.cc
===================================================================
--- chrome/browser/ui/views/tabs/tab_drag_controller.cc	(revision 256983)
+++ chrome/browser/ui/views/tabs/tab_drag_controller.cc	(working copy)
@@ -96,8 +96,9 @@
   ash::wm::WindowState* window_state =
       ash::wm::GetWindowState(tab_strip->GetWidget()->GetNativeWindow());
   return window_state->IsDocked() || window_state->IsSnapped();
+#else
+  return false;
 #endif
-  return false;
 }
 
 // Returns true if |bounds| contains the y-coordinate |y|. The y-coordinate