Fix a 'type-limits' warning in StringSlicer::FindValidBoundaryAfter

ui/gfx/text_elider.cc

Index: ui/gfx/text_elider.cc
diff --git a/ui/gfx/text_elider.cc b/ui/gfx/text_elider.cc
index 1bf85d4936761a22cf3351c4fa0e871abbf518bd..d21c211e3fb5e0137f87678191af235c9a382bdc 100644
--- a/ui/gfx/text_elider.cc
+++ b/ui/gfx/text_elider.cc
@@ -145,10 +145,17 @@ size_t StringSlicer::FindValidBoundaryBefore(size_t index) const {
 }
 
 size_t StringSlicer::FindValidBoundaryAfter(size_t index) const {
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wtype-limits"
+#endif

[Peter Kasting, 2014/10/29 17:08:00]

Definitely don't fix the warning this way -- the right answer is to change the
code so it doesn't produce the warning.

It's somewhat unfortunate that ICU defines all these methods as macros instead
of as functions.  I wonder if they'd ever be willing to change that.  We have
some ICU contributors on the team, you might ask them.

In the meantime, there are a couple obvious possible fixes here:

    U16_SET_CP_LIMIT(text_.c_str(), 0, index, -1);

or

    U16_SET_CP_LIMIT(text_.data(), 0, index,
                     base::checked_cast<int32_t>(text_.length()));

I'd probably do the former since it's simplest.

   DCHECK_LE(index, text_.length());
   if (index != text_.length())
     U16_SET_CP_LIMIT(text_.data(), 0, index, text_.length());
   return index;
+#if defined(__GCC__)
+#pragma GCC diagnostic pop
+#endif
 }
 
 base::string16 ElideFilename(const base::FilePath& filename,