Add NSString category for providing iOS6-style string drawing APIs.

ui/ios/NSString+CrStringDrawing.h

+// Copyright 2014 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.
+
+#ifndef UI_IOS_NSSTRING_CR_STRING_DRAWING_H_
+#define UI_IOS_NSSTRING_CR_STRING_DRAWING_H_
+
+#import <UIKit/UIKit.h>
+
+@interface NSString (CrStringDrawing)
+
+// Returns the size of the string if it were to be rendered with the specified
+// font on a single line. The width and height of the CGSize returned are
+// pixel-aligned.
+//
+// This method is a convenience wrapper around sizeWithAttributes: to avoid
+// boilerplate required to put |font| in a dictionary of attributes. Do not pass
+// nil into this method.
+- (CGSize)cr_pixelAlignedSizeWithFont:(UIFont*)font;
+
+// Deprecated: Use cr_pixelAlignedSizeWithFont: or sizeWithAttributes:
+// Provides a drop-in replacement for sizeWithFont:, which was deprecated in iOS
+// 7 in favor of -sizeWithAttributes:. Specifically, this method will return
+// CGSizeZero if |font| is nil, and the width and height returned are rounded up
+// to integer values.
+// TODO(lliabraa): This method was added to ease the transition off of the
+// deprecated sizeWithFont: method. New call sites should not be added and
+// existing call sites should be audited to determine the correct behavior for
+// nil |font| and rounding, then replaced with cr_pixelAlignedSizeWithFont: or
+// sizeWithAttributes: (crbug.com/364419).
+- (CGSize)cr_sizeWithFont:(UIFont*)font;
+
+@end
+
+#endif  // UI_IOS_NSSTRING_CR_STRING_DRAWING_H_