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 0d88e0f740a014a088b732b6340f8ca8bef0e15e..82000749ed97755646e9b2c8ab72fa8621b216c5 100644
--- a/third_party/WebKit/Source/core/editing/InputMethodController.cpp
+++ b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
@@ -31,8 +31,10 @@
 #include "core/dom/Text.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/Editor.h"
+#include "core/editing/commands/ReplaceSelectionCommand.h"
 #include "core/editing/commands/TypingCommand.h"
 #include "core/editing/markers/DocumentMarkerController.h"
+#include "core/editing/serializers/Serialization.h"
 #include "core/events/CompositionEvent.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLTextAreaElement.h"
@@ -468,6 +470,62 @@ 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();
+    int replaceStart = static_cast<int>(selectionStart);
+    int replaceEnd = static_cast<int>(selectionEnd);
+
+    Element* rootEditableElement = frame().selection().rootEditableElement();
+    if (!rootEditableElement)
+        return;
+
+    if (before > 0u) {
+        // In case of exceeding the left boundary.
+        before = std::min(selectionStart, before);

[Changwan Ryu, 2016/05/02 05:58:28]

This should be checked before the if statement. When selectionStart == 0, this
doesn't need to run.

+
+        // 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);
+        replaceStart = adjustedPosition.computeOffsetInContainerNode();
+    }
+
+    if (after > 0u) {
+        // 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;
+
+        // 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);
+        replaceEnd = adjustedPosition.computeOffsetInContainerNode();
+    }
+
+    String selectedText = frame().selection().selectedText();
+    if (!setSelectionOffsets(PlainTextRange(replaceStart, replaceEnd)))
+        return;
+    const EphemeralRange selectionRange = selectionOffsets.createRange(*rootEditableElement);
+    if (selectionRange.isNull())
+        return;
+    DocumentFragment* fragment = createFragmentFromText(selectionRange, selectedText);
+    ReplaceSelectionCommand::create(*frame().document(), fragment, ReplaceSelectionCommand::SelectReplacement)->apply();

[Changwan Ryu, 2016/05/02 05:58:28]

You shouldn't try to replace the selection with new text here.

Imagine we have <div contenteditable><b>a</b><i>b</i><b>c</b></div>, and "b" is
selected. Then replacing selection may also remove the style.

What is the reason Range::deleteContents() does not update HTMLElement's value?
Is there any event you need to dispatch?

+}
+
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);