Fix ManualTextFramerTest.OriginRTLTest on iOS 11

ios/chrome/browser/ui/util/manual_text_framer_unittest.mm

Index: ios/chrome/browser/ui/util/manual_text_framer_unittest.mm
diff --git a/ios/chrome/browser/ui/util/manual_text_framer_unittest.mm b/ios/chrome/browser/ui/util/manual_text_framer_unittest.mm
index 2b4e0e27d06e969da7f4b5d8aa92d76935974789..778527c3d5745d6aae1cba4496646397b8e88e6e 100644
--- a/ios/chrome/browser/ui/util/manual_text_framer_unittest.mm
+++ b/ios/chrome/browser/ui/util/manual_text_framer_unittest.mm
@@ -4,6 +4,7 @@
 
 #include "ios/chrome/browser/ui/util/manual_text_framer.h"
 
+#include "base/ios/ios_util.h"
 #include "base/mac/foundation_util.h"
 #include "base/time/time.h"
 #import "ios/chrome/browser/ui/util/core_text_util.h"
@@ -198,7 +199,11 @@ TEST_F(ManualTextFramerTest, OriginRTLTest) {
   attributes()[NSParagraphStyleAttributeName] = CreateParagraphStyle(
       20.0, NSTextAlignmentNatural, NSLineBreakByWordWrapping);
   ApplyAttributesForRange(text_range());
-  CGRect bounds = CGRectMake(0, 0, 100.0, 60.0);
+  // The bounds width is chosen so that the RTL string above is laid out into 3
+  // lines.  The font that iOS 11 uses for Arabic strings takes more horizontal
+  // space, so the bounds width is increased accordingly.
+  CGFloat width = base::ios::IsRunningOnIOS11OrLater() ? 130.0 : 100.0;

[rohitrao (ping after 24h), 2017/06/14 11:58:03]

This test is very dependent on the exact sizes of iOS font, because all of the
expected values are hardcoded.  Is there any way to write a meaningful test that
doesn't hardcode as much?

For example, could we determine the width by taking the length of the full
string and dividing by something close to 3?  How did you come up with 130.0?

[lpromero, 2017/06/15 08:26:51]

Dividing by 3 is not sufficient, I need to come up with some padding anyway.

What I did in my latest patch is just unconditionally bump the width (i.e. for
all configs). The box can be larger than necessary. The issue with iOS 11 was
that with the new font the text got clipped.
Now with the new value, it passes everywhere.

+  CGRect bounds = CGRectMake(0, 0, width, 60.0);
   FrameTextInBounds(bounds);
   CheckForLineCountAndFramedRange(3, text_range());
   for (FramedLine* line in text_frame().lines) {