Additional update on Pepper IME API and boilerplate thunk/proxy implementation.

ppapi/cpp/dev/ime_input_event_dev.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 PPAPI_CPP_DEV_IME_INPUT_EVENT_DEV_H_
 #define PPAPI_CPP_DEV_IME_INPUT_EVENT_DEV_H_
 
 #include <utility>
 
 #include "ppapi/c/dev/ppb_ime_input_event_dev.h"
@@ skipping 23 matching lines @@
   /// @return A string var representing the composition text. For non-IME
   /// input events the return value will be an undefined var.
   Var GetText() const;
 
   /// Returns the number of segments in the composition text.
   ///
   /// @return The number of segments. For events other than COMPOSITION_UPDATE,
   /// returns 0.
   uint32_t GetSegmentNumber() const;
 
-  /// Returns the start and the end position of the index-th segment in the
-  /// composition text. The positions are given by byte-indices of the string
-  /// GetText(). They always satisfy 0 <= .first < .second <= (Length of
-  /// GetText()) and GetSegmentAt(index).first < GetSegmentAt(index+1).first.
-  /// When the event is not COMPOSITION_UPDATE or index >= GetSegmentNumber(),
-  /// returns (0, 0).
+  /// Returns the position of the index-th segmentation point in the composition
+  /// text. The position is given by a byte-offset (not a character-offset) of
+  /// the string returned by GetText(). It always satisfies
+  /// 0=GetSegmentOffset(0) < ... < GetSegmentOffset(i) < GetSegmentOffset(i+1)
+  /// < ... < GetSegmentOffset(GetSegmentNumber())=(byte-length of GetText()).
+  /// Note that [GetSegmentOffset(i), GetSegmentOffset(i+1)) represents the
+  /// range of the i-th segment, and hence GetSegmentNumber() can be a valid
+  /// argument to this function instead of an off-by-1 error.
+  ///
+  /// @param[in] ime_event A <code>PP_Resource</code> corresponding to an IME
+  /// event.
   ///
   /// @param[in] index An integer indicating a segment.
   ///
-  /// @return A pair of integers representing the index-th segment.
-  std::pair<uint32_t, uint32_t> GetSegmentAt(uint32_t index) const;
+  /// @return The byte-offset of the segmentation point. If the event is not
+  /// COMPOSITION_UPDATE or index is out of range, returns 0.
+  uint32_t GetSegmentOffset(uint32_t index) const;
 
   /// Returns the index of the current target segment of composition.
   ///
   /// @return An integer indicating the index of the target segment. When there
   /// is no active target segment, or the event is not COMPOSITION_UPDATE,
   /// returns -1.
   int32_t GetTargetSegment() const;
 
   /// Returns the range selected by caret in the composition text.
   ///
   /// @return A pair of integers indicating the selection range.
   std::pair<uint32_t, uint32_t> GetSelection() const;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_DEV_IME_INPUT_EVENT_DEV_H_