[Mac] Omnibox keyword, keyword hint, and search hint support....

chrome/browser/cocoa/autocomplete_text_field_cell.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>
 
-// A cell that draws the autocomplete field.
+#include "base/scoped_nsobject.h"
+
+// AutocompleteTextFieldCell customizes the look of the Omnibox text
+// field.  The border and focus ring are modified, as is the font
+// baseline.
+
+// The cell also provides support for certain decorations to be
+// applied to the field.  These are the search hint ("Type to search"
+// on the right-hand side), the keyword hint ("Press [Tab] to search
+// Engine" on the right-hand side), and keyword mode ("Search Engine:"
+// in a button-like token on the left-hand side).
+//
+// The cell arranges the field-editor's placement via the standard
+// -editWithFrame:* and -selectWithFrame:* methods.  When the visible
+// decoration changes, the cell's look may change, and if the cell is
+// currently being edited the field editor will require adjustment.
+// The cell signals this requirement by returning YES for
+// -fieldEditorNeedsReset, which is used by AutocompleteTextField's
+// -resetFieldEditorFrameIfNeeded in testing if re-layout is needed.
 
 @interface AutocompleteTextFieldCell : NSTextFieldCell {
+ @private
+  // Set if there is a string to display in a rounded rect on the
+  // left-hand side of the field.  Exclusive WRT |hintString_|.
+  scoped_nsobject<NSAttributedString> keywordString_;
+
+  // Set if there is a string to display as a hint on the right-hand
+  // side of the field.  Exclusive WRT |keywordString_|;
+  scoped_nsobject<NSAttributedString> hintString_;
+
+  // YES if the info cell has been changed in a way which would result
+  // in the cell needing to be laid out again.
+  BOOL fieldEditorNeedsReset_;
 }
+
+@property BOOL fieldEditorNeedsReset;
+
+// TODO(shess): There should be two alternatives for
+// -setKeywordString:, the normal string and the min string.  Min can
+// be used when the text field's contents gets too wide to fit both it
+// and this.
+
+// The following setup |keywordString_| or |hintString_| based on the
+// input, and set |fieldEditorNeedsReset_| if the layout of the field
+// changed.
+- (void)setKeywordString:(NSString*)aString;
+- (void)setKeywordHintPrefix:(NSString*)prefixString
+                       image:(NSImage*)anImage
+                      suffix:(NSString*)suffixString;
+- (void)setSearchHintString:(NSString*)aString;
+- (void)clearKeywordAndHint;
+
 @end
+
+// Internal methods here exposed for unit testing.
+@interface AutocompleteTextFieldCell (UnitTesting)
+
+@property(readonly) NSAttributedString* keywordString;
+@property(readonly) NSAttributedString* hintString;
+
+// Return the portion of the cell to use for text display.
+- (NSRect)textFrameForFrame:(NSRect)cellFrame;
+
+@end