[ui/ios] Add helper methods for getting the bounding size of some text.

ui/ios/NSString+CrStringDrawing.h

Index: ui/ios/NSString+CrStringDrawing.h
diff --git a/ui/ios/NSString+CrStringDrawing.h b/ui/ios/NSString+CrStringDrawing.h
index 330593ea9d1c91275b8f3874a19749ca4aa9ec9c..71228023a124701745d4f9c69d220918584880e5 100644
--- a/ui/ios/NSString+CrStringDrawing.h
+++ b/ui/ios/NSString+CrStringDrawing.h
@@ -9,6 +9,26 @@
 
 @interface NSString (CrStringDrawing)
 
+// Calculates and returns the bounding rect for the receiver drawn using the
+// given size and font.
+// This method is implemented as a wrapper around
+// |boundingRectWithSize:options:attributes:context:| using the following values
+// for the parameters:
+//  - size: the provided |size|
+//  - options: NSStringDrawingUsesLineFragmentOrigin
+//  - attributes: a NSDictionary with the provided |font|.

[lpromero, 2014/11/06 16:17:44]

The period could go on the next line.

[lliabraa, 2014/11/06 16:35:47]

Done.

+//  - context: nil
+//
+// Note that the rect returned may contain fractional values.

[lpromero, 2014/11/06 16:17:43]

What do you think of:

+// Use |ceil| to raise the size values to the nearest higher integer.

[lliabraa, 2014/11/06 16:35:47]

I've opted to return fractional values to keep the API closer to the behavior of
the corresponding iOS method. It also allows the unittest to compare results
between this and the deprecated method.

+- (CGRect)cr_boundingRectWithSize:(CGSize)size
+                             font:(UIFont*)font;
+
+// Convenience wrapper to just return the size of |boundingRectWithSize:font:|.
+//
+// Note that the size returned may contain fractional values.

[lpromero, 2014/11/06 16:17:44]

Idem?

[lliabraa, 2014/11/06 16:35:47]

Acknowledged.

+- (CGSize)cr_boundingSizeWithSize:(CGSize)size
+                             font:(UIFont*)font;
+
 // 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.