Bug 1454945 - Get rid of nsIEditor.suppressDispatchingInputEvent since nobody uses it from JS r=m_kato

So, this patch replaces the setter with non-virtual method and removing the
getter since where is already non-virtual getter method.

MozReview-Commit-ID: Is19Yriz8t8

dom/html/nsTextEditorState.cpp

@@ -65,11 +65,11 @@ public:
   }
   ~ValueSetter()
   {
-    mTextEditor->SetSuppressDispatchingInputEvent(mOuterTransaction);
+    mTextEditor->SuppressDispatchingInputEvent(mOuterTransaction);
   }
   void Init()
   {
-    mTextEditor->SetSuppressDispatchingInputEvent(true);
+    mTextEditor->SuppressDispatchingInputEvent(true);
   }
 
 private: