[Mac] Strip newlines from paste.

chrome/browser/cocoa/autocomplete_text_field_editor.h

 // 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 <Cocoa/Cocoa.h>
 
+@protocol AutocompleteTextFieldEditorDelegateMethods
+
+// Delegate -paste: implementation to the field being edited.  If the
+// delegate returns YES, or does not implement the method, NSTextView
+// is called to handle the paste.  The delegate can block the paste
+// (or handle it internally) by returning NO.
+- (BOOL)textShouldPaste:(NSText*)fieldEditor;
+
+@end
+
 // Field editor used for the autocomplete field.
 @interface AutocompleteTextFieldEditor : NSTextView {
 }
 
 // Copy contents of the TextView to the designated clipboard as plain
 // text.
 - (void)performCopy:(NSPasteboard*)pb;
 
 // Same as above, note that this calls through to performCopy.
 - (void)performCut:(NSPasteboard*)pb;
+
+// Called by -paste: to decide whether to forward to superclass.
+// Exposed for unit testing.
+- (BOOL)shouldPaste;
+
 @end