Remove an unused FrameLoaderClient function

Remove an unused FrameLoaderClient function
https://bugs.webkit.org/show_bug.cgi?id=127628

Reviewed by Andreas Kling.

Source/WebCore:

All implementations of FrameLoaderClient::shouldStopLoadingForHistoryItem return true and this function
was only used by Chromium so we can get rid of it.

* loader/EmptyClients.h:
* loader/FrameLoaderClient.h:
* loader/HistoryController.cpp:
(WebCore::HistoryController::shouldStopLoadingForHistoryItem):

Source/WebKit/efl:

* WebCoreSupport/FrameLoaderClientEfl.cpp:
* WebCoreSupport/FrameLoaderClientEfl.h:

Source/WebKit/gtk:

* WebCoreSupport/FrameLoaderClientGtk.cpp:
* WebCoreSupport/FrameLoaderClientGtk.h:

Source/WebKit/mac:

* WebCoreSupport/WebFrameLoaderClient.h:
* WebCoreSupport/WebFrameLoaderClient.mm:

Source/WebKit/win:

* WebCoreSupport/WebFrameLoaderClient.cpp:
* WebCoreSupport/WebFrameLoaderClient.h:

Source/WebKit/wince:

* WebCoreSupport/FrameLoaderClientWinCE.cpp:
* WebCoreSupport/FrameLoaderClientWinCE.h:

Source/WebKit2:

* WebProcess/WebCoreSupport/WebFrameLoaderClient.cpp:
* WebProcess/WebCoreSupport/WebFrameLoaderClient.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@162786 268f45cc-cd09-0410-ab3c-d52691b4dbfc