Merge notifyComponentsOnChangedSelection into respondToSelectionChange

Merge notifyComponentsOnChangedSelection into respondToSelectionChange
https://bugs.webkit.org/show_bug.cgi?id=128993

Reviewed by Andreas Kling.

Merged notifyComponentsOnChangedSelection into respondToSelectionChange since notifyComponentsOnChangedSelection
was only added in iOS codebase in response to the code added for continuous spellchecking and alternative text controller
in respondToChangedSelection but they should have been called inside setIgnoreCompositionSelectionChange.

So merge these two functions and make respondToChangedSelection behave like setIgnoreCompositionSelectionChange.

* editing/Editor.cpp:
(WebCore::Editor::setIgnoreCompositionSelectionChange):
(WebCore::Editor::respondToChangedSelection):
* editing/Editor.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@164320 268f45cc-cd09-0410-ab3c-d52691b4dbfc