-[AutocompleteTextFieldEditor delegate] cleanup

chrome/browser/cocoa/autocomplete_text_field_editor.mm

 // Copyright (c) 2010 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 "app/l10n_util_mac.h"
 #include "base/string_util.h"
 #include "grit/generated_resources.h"
 #include "base/sys_string_conversions.h"
@@ skipping 29 matching lines @@
     observer->OnCopy();
 }
 
 - (void)cut:(id)sender {
   [self copy:sender];
   [self delete:nil];
 }
 
 // This class assumes that the delegate is an AutocompleteTextField.
 // Enforce that assumption.
-- (void)setDelegate:(id)anObject {
-  DCHECK(anObject == nil ||
-         [anObject isKindOfClass:[AutocompleteTextField class]]);
-  [super setDelegate:anObject];
+- (AutocompleteTextField*)delegate {
+  AutocompleteTextField* delegate =
+      static_cast<AutocompleteTextField*>([super delegate]);
+  DCHECK(delegate == nil ||
+         [delegate isKindOfClass:[AutocompleteTextField class]]);
+  return delegate;
+}
+
+- (void)setDelegate:(AutocompleteTextField*)delegate {
+  DCHECK(delegate == nil ||
+         [delegate isKindOfClass:[AutocompleteTextField class]]);
+  [super setDelegate:delegate];
 }
 
 // Convenience method for retrieving the observer from the delegate.
 - (AutocompleteTextFieldObserver*)observer {
-  DCHECK([[self delegate] isKindOfClass:[AutocompleteTextField class]]);
-  return [static_cast<AutocompleteTextField*>([self delegate]) observer];
+  return [[self delegate] observer];
 }
 
 - (void)paste:(id)sender {
   AutocompleteTextFieldObserver* observer = [self observer];
   DCHECK(observer);
   if (observer) {
     observer->OnPaste();
   }
 }
 
@@ skipping 68 matching lines @@
       [item setTag:IDC_EDIT_SEARCH_ENGINES];
     }
   }
 
   return menu;
 }
 
 // (Overridden from NSResponder)
 - (BOOL)becomeFirstResponder {
   BOOL doAccept = [super becomeFirstResponder];
-  AutocompleteTextField* field = (AutocompleteTextField*)[self delegate];
+  AutocompleteTextField* field = [self delegate];
   // Only lock visibility if we've been set up with a delegate (the text field).
   if (doAccept && field) {
-    DCHECK([field isKindOfClass:[AutocompleteTextField class]]);
     // Give the text field ownership of the visibility lock. (The first
     // responder dance between the field and the field editor is a little
     // weird.)
     [[BrowserWindowController browserWindowControllerForView:field]
         lockBarVisibilityForOwner:field withAnimation:YES delay:NO];
   }
   return doAccept;
 }
 
 // (Overridden from NSResponder)
 - (BOOL)resignFirstResponder {
   BOOL doResign = [super resignFirstResponder];
-  AutocompleteTextField* field = (AutocompleteTextField*)[self delegate];
+  AutocompleteTextField* field = [self delegate];
   // Only lock visibility if we've been set up with a delegate (the text field).
   if (doResign && field) {
-    DCHECK([field isKindOfClass:[AutocompleteTextField class]]);
     // Give the text field ownership of the visibility lock.
     [[BrowserWindowController browserWindowControllerForView:field]
         releaseBarVisibilityForOwner:field withAnimation:YES delay:YES];
   }
   return doResign;
 }
 
 // (URLDropTarget protocol)
 - (id<URLDropTargetController>)urlDropController {
   BrowserWindowController* windowController =
@@ skipping 48 matching lines @@
 
   // TODO(shess): Beep on empty?  I hate beeps, though.
   // NOTE: If |aString| is empty, this intentionally replaces the
   // selection with empty.  This seems consistent with the case where
   // the input contained a mixture of characters and the string ended
   // up not empty.
   [super insertText:aString];
 }
 
 @end