Reland: Fix setComposingText with empty text when newCursorPosition != 1

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..661aca2fd3d9026b5b6054d730a3347f07e9d82f 100644
--- a/third_party/WebKit/Source/core/editing/InputMethodController.cpp
+++ b/third_party/WebKit/Source/core/editing/InputMethodController.cpp
@@ -321,6 +321,10 @@ void InputMethodController::setComposition(const String& text, const Vector<Comp
     if (!target)
         return;
 
+    int selectionOffsetsStart = static_cast<int>(getSelectionOffsets().start());
+    int start = selectionOffsetsStart + selectionStart;
+    int end = selectionOffsetsStart + selectionEnd;
+

[yosin_UTC9, 2016/06/15 05:34:41]

Could you add DCHECK_XX() to validate |start| and |end| have valid values?

[yosin_UTC9, 2016/06/15 19:00:21]

I mean

DCHECK_GE(selctionStart, 0);
DCHECK_LE(selectionStart, selectionEnd);

     // Dispatch an appropriate composition event to the focused node.
     // We check the composition status and choose an appropriate composition event since this
     // function is used for three purposes:
@@ -339,11 +343,13 @@ void InputMethodController::setComposition(const String& text, const Vector<Comp
     if (text.isEmpty()) {
         if (hasComposition()) {
             confirmComposition(emptyString());
-            return;
+        } else {
+            // It's weird to call |setComposition()| with empty text outside composition, however some IME
+            // (e.g. Japanese IBus-Anthy) did this, so we simply delete selection without sending extra events.
+            TypingCommand::deleteSelection(*frame().document(), TypingCommand::PreventSpellChecking);
         }
-        // It's weird to call |setComposition()| with empty text outside composition, however some IME
-        // (e.g. Japanese IBus-Anthy) did this, so we simply delete selection without sending extra events.
-        TypingCommand::deleteSelection(*frame().document(), TypingCommand::PreventSpellChecking);
+
+        setEditableSelectionOffsets(PlainTextRange(start, end));
         return;
     }
 
@@ -390,30 +396,11 @@ void InputMethodController::setComposition(const String& text, const Vector<Comp
     if (baseNode->layoutObject())
         baseNode->layoutObject()->setShouldDoFullPaintInvalidation();
 
-    // In case of exceeding the left boundary.
-    int selectionOffsetsStart = static_cast<int>(getSelectionOffsets().start());
-    int start = std::max(selectionOffsetsStart + selectionStart, 0);
-    int end = std::max(selectionOffsetsStart + selectionEnd, start);
-
     Element* rootEditableElement = frame().selection().rootEditableElement();
     if (!rootEditableElement)
         return;
 
-    // In case of exceeding the right boundary.
-    // If both |value1| and |value2| exceed right boundary,
-    // PlainTextRange(value1, value2)::createRange() will return a default
-    // value, which is [0,0]. In order to get the correct Position in that case,
-    // we should make sure |value1| is within range at least.
-    const EphemeralRange& startRange = PlainTextRange(0, start).createRange(*rootEditableElement);
-    const EphemeralRange& endRange = PlainTextRange(0, end).createRange(*rootEditableElement);
-
-    // TODO(yabinh): There should be a better way to create |startPosition| and
-    // |endPosition|. But for now, since we can't get |anchorNode| and |offset|,
-    // we can't create the 2 Position objects directly. So we use
-    // PlainTextRange::createRange as a workaround.
-    const Position& startPosition = startRange.endPosition();
-    const Position& endPosition = endRange.endPosition();
-    const EphemeralRange selectedRange(startPosition, endPosition);
+    const EphemeralRange selectedRange = PlainTextRange(start, end).createRange(*rootEditableElement);

[yosin_UTC9, 2016/06/15 05:34:41]

s/const EphemeralRange/const EphmeralRange&/
to avoid copy.

     frame().selection().setSelectedRange(selectedRange, TextAffinity::Downstream, SelectionDirectionalMode::NonDirectional, NotUserTriggered);
 
     if (underlines.isEmpty()) {