Revert of Avoid style clobbering in setCompositionFromExistingText.

Source/core/editing/InputMethodController.h

Index: Source/core/editing/InputMethodController.h
diff --git a/Source/core/editing/InputMethodController.h b/Source/core/editing/InputMethodController.h
index 80e9ce9fb6b48d94b450f665cad3aedaaa3d7863..571bd41c01fa7c92c76d9913332f32406b047976 100644
--- a/Source/core/editing/InputMethodController.h
+++ b/Source/core/editing/InputMethodController.h
@@ -27,7 +27,6 @@
 #define InputMethodController_h
 
 #include "core/CoreExport.h"
-#include "core/dom/Range.h"
 #include "core/editing/CompositionUnderline.h"
 #include "core/editing/EphemeralRange.h"
 #include "core/editing/PlainTextRange.h"
@@ -73,6 +72,13 @@
     EphemeralRange compositionEphemeralRange() const;
     PassRefPtrWillBeRawPtr<Range> compositionRange() const;
 
+    // getting international text input composition state (for use by InlineTextBox)
+    Text* compositionNode() const { return m_compositionNode.get(); }
+    unsigned compositionStart() const { return m_compositionStart; }
+    unsigned compositionEnd() const { return m_compositionEnd; }
+    bool compositionUsesCustomUnderlines() const { return !m_customCompositionUnderlines.isEmpty(); }
+    const Vector<CompositionUnderline>& customCompositionUnderlines() const { return m_customCompositionUnderlines; }
+
     void clear();
 
     PlainTextRange getSelectionOffsets() const;
@@ -94,9 +100,13 @@
     friend class SelectionOffsetsScope;
 
     RawPtrWillBeMember<LocalFrame> m_frame;
-    RefPtrWillBeMember<Range> m_compositionRange;
-    bool m_isDirty;
-    bool m_hasComposition;
+    RefPtrWillBeMember<Text> m_compositionNode;
+    // We don't use PlainTextRange which is immutable, for composition range.
+    unsigned m_compositionStart;
+    unsigned m_compositionEnd;
+    // startOffset and endOffset of CompositionUnderline are based on
+    // m_compositionNode.
+    Vector<CompositionUnderline> m_customCompositionUnderlines;
 
     explicit InputMethodController(LocalFrame&);