Fix ibus-m17n crash due to wrong parameter from Chrome.

ui/base/ime/input_method_ibus.cc

 // Copyright (c) 2012 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.
 
 #include "ui/base/ime/input_method_ibus.h"
 
 #include <X11/X.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #undef FocusIn
@@ skipping 249 matching lines @@
     return;
   }
 
   if (previous_selection_range_ == selection_range &&
       previous_surrounding_text_ == surrounding_text)
     return;
 
   previous_selection_range_ = selection_range;
   previous_surrounding_text_ = surrounding_text;
 
-  // In the original meaning of SetSurroundingText is not just selection text,
-  // but currently there are no way to retrieve surrounding text in
-  // TextInputClient.
+  // Here SetSurroundingText accepts relative position of |surrounding_text|, so
+  // we have to convert |selection_range| from node coordinates to
+  // |surrounding_text| coordinates.
   GetInputContextClient()->SetSurroundingText(
       UTF16ToUTF8(surrounding_text),
-      selection_range.start(), /* cursor position. */
-      selection_range.end()); /* selection anchor position. */
+      selection_range.start() - text_range.start(),
+      selection_range.end() - text_range.start());
 }
 
 void InputMethodIBus::CancelComposition(const TextInputClient* client) {
   if (context_focused_ && IsTextInputClientFocused(client))
     ResetContext();
 }
 
 std::string InputMethodIBus::GetInputLocale() {
   // Not supported.
   return "";
@@ skipping 646 matching lines @@
   }
 
   // Use a black thin underline by default.
   if (out_composition->underlines.empty()) {
     out_composition->underlines.push_back(CompositionUnderline(
         0, length, SK_ColorBLACK, false /* thick */));
   }
 }
 
 }  // namespace ui