[Mac] Fix for security indicator drag&drop navigation

chrome/browser/ui/cocoa/location_bar/autocomplete_text_field.mm

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/location_bar/autocomplete_text_field.h"
 
 #include "base/logging.h"
 #import "base/mac/mac_util.h"
 #import "base/mac/sdk_forward_declarations.h"
 #include "chrome/browser/themes/theme_service.h"
@@ skipping 495 matching lines @@
   return [windowController toolbarController];
 }
 
 // (URLDropTarget protocol)
 - (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender {
   // Make ourself the first responder, which will select the text to indicate
   // that our contents would be replaced by a drop.
   // TODO(viettrungluu): crbug.com/30809 -- this is a hack since it steals focus
   // and doesn't return it.
   [[self window] makeFirstResponder:self];
-  return [dropHandler_ draggingEntered:sender];
+
+  bool canDropAtLocation =
+      [[self cell] canDropAtLocationInWindow:[sender draggingLocation]
+                                      ofView:self];
+  return canDropAtLocation ? [dropHandler_ draggingEntered:sender]
+                           : NSDragOperationNone;
 }
 
 // (URLDropTarget protocol)
 - (NSDragOperation)draggingUpdated:(id<NSDraggingInfo>)sender {
-  return [dropHandler_ draggingUpdated:sender];
+  bool canDropAtLocation =
+      [[self cell] canDropAtLocationInWindow:[sender draggingLocation]
+                                      ofView:self];
+  return canDropAtLocation ? [dropHandler_ draggingUpdated:sender]
+                           : NSDragOperationNone;
 }
 
 // (URLDropTarget protocol)
 - (void)draggingExited:(id<NSDraggingInfo>)sender {
   return [dropHandler_ draggingExited:sender];
 }
 
 // (URLDropTarget protocol)
 - (BOOL)performDragOperation:(id<NSDraggingInfo>)sender {
   return [dropHandler_ performDragOperation:sender];
@@ skipping 54 matching lines @@
                                   NSMinY(frame),
                                   suggestWidth,
                                   NSHeight(frame));
 
   gfx::ScopedNSGraphicsContextSaveGState saveGState;
   NSRectClip(suggestRect);
   [cell drawInteriorWithFrame:frame inView:controlView];
 }
 
 }  // namespace autocomplete_text_field