Checked if mInputStyle has changed.

Checked if mInputStyle has changed.

If InsertText () is called while mEventData-> mInputStyle is not yet set to defaultInputStyle(),
it will behave wrong action.

ex) corner case :
  style.size = 30 but mImpl->mEventData->mInputStyle.size = 0 in InsertText()
  then this code will behave wrong action.
  const bool addFontSizeRun = style.size != mImpl->mEventData->mInputStyle.size;

  Normally, ProcessInputEvents () is called before InsertText(),
  and the value of mImpl-> mEventData-> mInputStyle.size is set to 30.
  So there is usually no problem.

Change-Id: I7ac15fe4b1bdd55c224e43a23c389fcd74a093a3