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..43134e77cf75c7f1c6f8b46c66edf774e752eacf 100644
--- a/ui/gfx/text_elider.cc
+++ b/ui/gfx/text_elider.cc
@@ -17,6 +17,7 @@
 #include "base/i18n/char_iterator.h"
 #include "base/i18n/rtl.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
@@ -146,8 +147,12 @@ size_t StringSlicer::FindValidBoundaryBefore(size_t index) const {
 
 size_t StringSlicer::FindValidBoundaryAfter(size_t index) const {
   DCHECK_LE(index, text_.length());
-  if (index != text_.length())
-    U16_SET_CP_LIMIT(text_.data(), 0, index, text_.length());
+  if (index != text_.length()) {
+    int32_t text_index = base::checked_cast<int32_t>(index);
+    int32_t text_length = base::checked_cast<int32_t>(text_.length());
+    U16_SET_CP_LIMIT(text_.data(), 0, text_index, text_length);
+    index = base::checked_cast<size_t>(text_index);

[Peter Kasting, 2014/10/29 19:17:26]

How about this:

  if (index == text_.length())
    return index;
  int32_t text_index = ...
  ...
  return static_cast<size_t>(text_index);

It should be OK to use a static_cast in the return statement since
text_.length() successfully checked_casted to an int32_t.  And this
restructuring of the code makes it harder for someone in the future to break the
code by not returning the updated value.

+  }
   return index;
 }