base/i18n: Pass |str| as const reference in BreakIterator::Init().

base/i18n/break_iterator.h

Index: base/i18n/break_iterator.h
diff --git a/base/i18n/break_iterator.h b/base/i18n/break_iterator.h
index acd5c304986649ee9e480c8617fa509f70455217..82e8092632c94eae1e60c9848f38aa16e7cc8559 100644
--- a/base/i18n/break_iterator.h
+++ b/base/i18n/break_iterator.h
@@ -67,7 +67,7 @@ class BreakIterator {
   };
 
   // Requires |str| to live as long as the BreakIterator does.
-  BreakIterator(const string16* str, BreakType break_type);
+  BreakIterator(const string16& str, BreakType break_type);
   ~BreakIterator();
 
   // Init() must be called before any of the iterators are valid.
@@ -106,7 +106,7 @@ class BreakIterator {
   void* iter_;
 
   // The string we're iterating over.
-  const string16* string_;
+  const string16& string_;
 
   // The breaking style (word/space/newline).
   BreakType break_type_;