[Mac] Strip newlines from paste.

chrome/browser/cocoa/autocomplete_text_field_editor.mm

 // Copyright (c) 2009 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/cocoa/autocomplete_text_field_editor.h"
 
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
 
 @implementation AutocompleteTextFieldEditor
@@ skipping 12 matching lines @@
   [pb declareTypes:[NSArray array] owner:nil];
   [self writeSelectionToPasteboard:pb types:
       [NSArray arrayWithObject:NSStringPboardType]];
 }
 
 - (void)performCut:(NSPasteboard*)pb {
   [self performCopy:pb];
   [self delete:nil];
 }
 
+- (BOOL)shouldPaste {
+  id delegate = [self delegate];
+  if (![delegate respondsToSelector:@selector(textShouldPaste:)] ||
+      [delegate textShouldPaste:self]) {
+    return YES;
+  }
+  return NO;
+}
+
+- (void)paste:(id)sender {
+  if ([self shouldPaste]) {
+    [super paste:sender];
+  }
+}
+
 @end