Switch the offset conversion routines from...

base/strings/utf_offset_string_conversions.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_
 #define BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 26 matching lines @@
     std::vector<size_t>* offsets_for_adjustment);
 
 BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffset(
     const base::StringPiece16& utf16,
     size_t* offset_for_adjustment);
 BASE_EXPORT std::string UTF16ToUTF8AndAdjustOffsets(
     const base::StringPiece16& utf16,
     std::vector<size_t>* offsets_for_adjustment);
 
 // Limiting function callable by std::for_each which will replace any value
-// which is equal to or greater than |limit| with npos.
+// which is greater than |limit| with npos.

[msw, 2013/09/04 23:58:50]

I share Will's concern that other callers might have properly expected the old
behavior. Some callers might try size_t i = 1; std::string text = "a";
LimitOffset(...text.length()...); ...text[i]... or similar.

Can you point to the codepath by which SearchProvider exercises this code?

[Peter Kasting, 2013/09/05 20:11:59]

See bug 284781 comment 16 for the full description.

 template <typename T>
 struct LimitOffset {
   explicit LimitOffset(size_t limit)
     : limit_(limit) {}
 
   void operator()(size_t& offset) {
-    if (offset >= limit_)
+    if (offset > limit_)
       offset = T::npos;
   }
 
   size_t limit_;
 };
 
 // Stack object which, on destruction, will update a vector of offsets based on
 // any supplied adjustments.  To use, declare one of these, providing the
 // address of the offset vector to adjust.  Then Add() any number of Adjustments
 // (each Adjustment gives the |original_offset| of a substring and the lengths
@@ skipping 19 matching lines @@
  private:
   void AdjustOffset(std::vector<size_t>::iterator offset);
 
   std::vector<size_t>* offsets_for_adjustment_;
   std::vector<Adjustment> adjustments_;
 };
 
 }  // namespace base
 
 #endif  // BASE_STRINGS_UTF_OFFSET_STRING_CONVERSIONS_H_