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 b70befe6440a692d856ddb169fc145088ea45c63..69588e7fff7c376f02939a3e310771da840c4a06 100644
--- a/third_party/WebKit/Source/core/editing/InputMethodController.cpp
+++ b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
@@ -489,6 +489,77 @@ 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();
+    Element* rootEditableElement = frame().selection().rootEditableElement();
+    if (!rootEditableElement)
+        return;
+
+    bool deleteBeforeText = before > 0u && selectionStart > 0u;
+    bool deleteAftertext = after > 0u;
+
+    if (deleteBeforeText) {
+        // In case of exceeding the left boundary.
+        int deletionStart = selectionStart - std::min(selectionStart, before);
+
+        // Delete the text before selectionStart.
+        // For multi-code text, we can't delete it successfully if we only
+        // delete the right half of it. So we need to adjust the start of
+        // deletion.
+        const EphemeralRange& startRange = PlainTextRange(0, deletionStart).createRange(*rootEditableElement);
+        const Position& startPosition = startRange.endPosition();
+        Node* anchorNode = startPosition.anchorNode();
+        int deletionStartInContainerNode = startPosition.computeOffsetInContainerNode();
+
+        const Position position(anchorNode, deletionStartInContainerNode + 1);
+        const Position& adjustedPosition = previousPositionOf(position, PositionMoveType::GraphemeCluster);
+        int adjustedDeletionStart = adjustedPosition.computeOffsetInContainerNode();
+
+        Range* deletedRange = Range::create(*frame().document(), adjustedPosition, frame().selection().start());
+        deletedRange->deleteContents(ASSERT_NO_EXCEPTION);
+
+        size_t deletedLength = selectionStart - static_cast<size_t>(deletionStart + deletionStartInContainerNode - adjustedDeletionStart);
+        selectionEnd = selectionEnd - deletedLength;
+    }
+
+    if (deleteAftertext) {
+        // In case of exceeding the right boundary.
+        PlainTextRange range(static_cast<int>(selectionEnd), static_cast<int>(selectionEnd + after));
+        if (range.isNull())
+            return;
+        const EphemeralRange adjustedRange = range.createRange(*rootEditableElement);
+        if (adjustedRange.isNull())
+            return;
+
+        const Position& endPosition = adjustedRange.endPosition();
+        Node* anchorNode = endPosition.anchorNode();
+        int deletionEndInContainerNode = endPosition.computeOffsetInContainerNode();
+
+        // Delete the text after selectionEnd.
+        // We also need to adjust the end of deletion for multi-code text.
+        Position position(anchorNode, deletionEndInContainerNode - 1);
+        Position adjustedPosition = nextPositionOf(position, PositionMoveType::GraphemeCluster);
+
+        Range* deletedRange = Range::create(*frame().document(), frame().selection().end(), adjustedPosition);
+        deletedRange->deleteContents(ASSERT_NO_EXCEPTION);
+    }
+
+    if (deleteBeforeText  || deleteAftertext) {
+        rootEditableElement->dispatchEvent(Event::create(EventTypeNames::webkitEditableContentChanged));
+    }
+
+    if (deleteBeforeText) {
+        rootEditableElement->dispatchEvent(Event::create(EventTypeNames::selectionchange));
+    }
+}
+
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);