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 0bd3b86d91b2380d6a7380e89bc63feae01cc7e0..d52dfd8e4d401e0e0ab59b7d555b3ca7e8171d11 100644
--- a/third_party/WebKit/Source/core/editing/InputMethodController.cpp
+++ b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
@@ -548,6 +548,63 @@ void InputMethodController::extendSelectionAndDelete(int before, int after)
     TypingCommand::deleteSelection(*frame().document());
 }
 
+void InputMethodController::deleteSurroundingText(size_t before, size_t after)

[Changwan Ryu, 2016/06/20 10:03:24]

Could you add a TODO to reduce the number of selectionchanged events?

[yabinh, 2016/06/20 10:22:23]

Acknowledged.

+{
+    if (!editor().canEdit())
+        return;
+    PlainTextRange selectionOffsets(getSelectionOffsets());
+    if (selectionOffsets.isNull())
+        return;
+
+    size_t selectionStart = selectionOffsets.start();
+    size_t selectionEnd = selectionOffsets.end();
+
+    if (before > 0u && selectionStart > 0u) {
+        // In case of exceeding the left boundary.
+        before = std::min(selectionStart, before);
+
+        // Select the text to be deleted before selectionStart.
+        // For multi-code text, we can't select it successfully if we only
+        // select the right half of it. So we need to adjust the start of
+        // selection.
+        Position position(frame().selection().start().anchorNode(), selectionStart - before + 1);
+        Position adjustedPosition = previousPositionOf(position, 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 > 0u) {
+        // Adjust the deleted range in case of exceeding the right boundary.
+        PlainTextRange range(static_cast<int>(selectionEnd), static_cast<int>(selectionEnd + after));
+        if (range.isNull())
+            return;
+        Element* rootEditableElement = frame().selection().rootEditableElement();
+        if (!rootEditableElement)
+            return;
+        const EphemeralRange adjustedRange = range.createRange(*rootEditableElement);
+        if (adjustedRange.isNull())
+            return;
+
+        // Select the text to be deleted after selectionEnd.
+        // We also need to adjust the end of selection for multi-code text.
+        Position position(frame().selection().start().anchorNode(), adjustedRange.endPosition().computeOffsetInContainerNode() - 1);
+        Position adjustedPosition = nextPositionOf(position, PositionMoveType::GraphemeCluster);
+        int adjustedEnd = adjustedPosition.computeOffsetInContainerNode();
+
+        if (!setSelectionOffsets(PlainTextRange(static_cast<int>(selectionEnd), adjustedEnd)))
+            return;
+        TypingCommand::deleteSelection(*frame().document());
+    }
+
+    setSelectionOffsets(PlainTextRange(selectionStart, selectionEnd));
+}
+
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);