-[AutocompleteTextFieldEditor delegate] cleanup.

AutocompleteTextFieldEditor* requires its delegate to be an
AutocompleteTextField*.  Override the return type of -delegate and the
parameter type of -setDelegate:.  This is safe because NSTextView,
AutocompleteTextFieldEditor's superclass, uses id<NSTextViewDelegate> as the
delegate type (as of the 10.6 SDK, and just id prior), and
AutocompleteTextField* implements NSTextViewDelegate (and of course is
descended from id).

This change allows some casts and scattered type checks in this file to be
removed in favor of the cast and type check in one central location.  It also
fixes another 10.6 SDK build error caused because -delegate is more specific
than just id in that SDK.  It provides future-proofing against further errors
of this sort.

BUG=none
TEST=10.6 SDK build
Review URL: http://codereview.chromium.org/1550002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43083 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 21 insertions, 10 deletions

diff --git a/chrome/browser/cocoa/autocomplete_text_field_editor.h b/chrome/browser/cocoa/autocomplete_text_field_editor.h
index aee4e6a..1c3ce5a 100644
--- a/chrome/browser/cocoa/autocomplete_text_field_editor.h
+++ b/chrome/browser/cocoa/autocomplete_text_field_editor.h
@@ -7,6 +7,7 @@
 #include "base/scoped_nsobject.h"
 #import "chrome/browser/cocoa/url_drop_target.h"
 
+@class AutocompleteTextField;
 class AutocompleteTextFieldObserver;
 class Profile;
 
@@ -33,6 +34,11 @@ class Profile;
 
 @property(nonatomic) Profile* profile;
 
+// The delegate is always an AutocompleteTextField*.  Override the superclass
+// implementations to allow for proper typing.
+- (AutocompleteTextField*)delegate;
+- (void)setDelegate:(AutocompleteTextField*)delegate;
+
 @end
 
 @interface AutocompleteTextFieldEditor(PrivateTestMethods)
diff --git a/chrome/browser/cocoa/autocomplete_text_field_editor.mm b/chrome/browser/cocoa/autocomplete_text_field_editor.mm
index 5608e3f..70aa5cd 100644
--- a/chrome/browser/cocoa/autocomplete_text_field_editor.mm
+++ b/chrome/browser/cocoa/autocomplete_text_field_editor.mm
@@ -47,16 +47,23 @@ class Extension;
 
 // 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 {
@@ -145,10 +152,9 @@ class Extension;
 // (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.)
@@ -161,10 +167,9 @@ class Extension;
 // (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];