Fix InputConnection.deleteSurroundingText()

third_party/WebKit/Source/core/editing/InputMethodController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 454 matching lines @@
             return;
         if (before == 0)
             break;
         ++before;
     } while (frame().selection().start() == frame().selection().end() && before <= static_cast<int>(selectionOffsets.start()));
     // TODO(chongz): According to spec |data| should be "forward" or "backward".
     dispatchBeforeInputEditorCommand(frame().document()->focusedElement(), InputEvent::InputType::DeleteContent);
     TypingCommand::deleteSelection(*frame().document());
 }
 
+void InputMethodController::deleteSurroundingText(size_t before, size_t after)
+{
+    if (!editor().canEdit())
+        return;
+    PlainTextRange selectionOffsets(getSelectionOffsets());
+    if (selectionOffsets.isNull())
+        return;
+
+    size_t selectionStart = selectionOffsets.start();
+    size_t selectionEnd = selectionOffsets.end();
+
+    if (before != 0) {

[Changwan Ryu, 2016/04/26 05:36:30]

before > 0u

+        before = std::min(selectionStart, before);
+
+        // Select the text to be deleted before selectionStart,
+        // and adjust the start of selection in case of multi-code text.
+        Position basePosition(frame().selection().start().anchorNode(), selectionStart - before + 1);
+        Position adjustedPosition = previousPositionOf(basePosition, PositionMoveType::GraphemeCluster);
+        int adjustedStart = adjustedPosition.computeOffsetInContainerNode();
+
+        if (!setSelectionOffsets(PlainTextRange(adjustedStart, static_cast<int>(selectionStart))))
+            return;
+        TypingCommand::deleteSelection(*frame().document());
+
+        selectionEnd = selectionEnd - (selectionStart - adjustedStart);
+        selectionStart = adjustedStart;
+    }
+
+    if (after != 0) {

[Changwan Ryu, 2016/04/26 05:36:30]

after > 0u

Comment still missing: why do you need to adjust 'before' and not 'after'?

+        if (!setSelectionOffsets(PlainTextRange(static_cast<int>(selectionEnd), static_cast<int>(selectionEnd + after))))
+            return;
+        TypingCommand::deleteSelection(*frame().document());
+    }
+
+    setSelectionOffsets(PlainTextRange(selectionStart, selectionEnd));
+}
+
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionRange);
 }
 
 } // namespace blink