[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 {
+  LocationBarDecoration* decoration =
+      [[self cell] decorationForEvent:[NSApp currentEvent]

[shrike, 2016/09/07 23:49:27]

Relying on [NSApp currentEvent] for the drag event makes me nervous. It's
probably better to call [sender draggingLocation] to get the mouse location, and
to pass that to a version of decorationForEvent that takes a mouse point.

[spqchan, 2016/09/08 17:41:43]

Done.

+                               inRect:[self bounds]
+                               ofView:self];
+  if (decoration)
+    return NSDragOperationNone;
+
   return [dropHandler_ draggingUpdated:sender];
 }
 
 // (URLDropTarget protocol)
 - (void)draggingExited:(id<NSDraggingInfo>)sender {
   return [dropHandler_ draggingExited:sender];
 }
 
 // (URLDropTarget protocol)
 - (BOOL)performDragOperation:(id<NSDraggingInfo>)sender {
@@ skipping 55 matching lines @@
                                   NSMinY(frame),
                                   suggestWidth,
                                   NSHeight(frame));
 
   gfx::ScopedNSGraphicsContextSaveGState saveGState;
   NSRectClip(suggestRect);
   [cell drawInteriorWithFrame:frame inView:controlView];
 }
 
 }  // namespace autocomplete_text_field