[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 500 matching lines @@
   // 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];
 }
 
 // (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]

[shrike, 2016/09/16 18:28:41]

I think you need to add canDropAtLocation logic to draggingEntered: as well? I
noticed that if I drag to the left out of the Omnibox, and then slowly drag back
to the right, when I reach the left edge of the Omnibox I get a green plus
cursor for a moment, and then an arrow cursor. I suspect draggingEntered: is
returning YES, and then the Appkit is immediately follows up with a call to
draggingUpdated:, which returns NO.

[spqchan, 2016/09/20 21:00:00]

Done.

+                           : 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