Fix InputConnection.deleteSurroundingText()

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

Index: third_party/WebKit/Source/core/editing/InputMethodController.cpp
diff --git a/third_party/WebKit/Source/core/editing/InputMethodController.cpp b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
index ca051a0c662ea21fe8e1dd82ca3db819b1c1d4e9..1edbc2c0fbc8ea335473ab90a585deda277ae298 100644
--- a/third_party/WebKit/Source/core/editing/InputMethodController.cpp
+++ b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
@@ -472,6 +472,43 @@ void InputMethodController::extendSelectionAndDelete(int before, int after)
     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);