https://bugs.webkit.org/show_bug.cgi?id=122064

Reviewed by Andreas Kling.

Source/WebCore:

* WebCore.exp.in: Removed exports of FrameView::isMainFrameView and
Page::frameIsMainFrame. Since the new isMainFrame function is inline, it
does not need to be exported.

* history/PageCache.cpp:
(WebCore::PageCache::markPagesForFullStyleRecalc):
(WebCore::PageCache::markPagesForDeviceScaleChanged):
These two were the only functions I found that really wanted the equivalent
of Page::frameIsMainFrame, so wrote it out here instead of using a function
call.

* inspector/InspectorAgent.cpp: Removed the unused isMainResourceLoader function.
* inspector/InspectorAgent.h: Removed declarations of a few nonexistent or
unused private member functions. Also removed the InjectedScriptForOriginMap
typedef: It's mor readable to use the type directly

* loader/FrameLoader.h: Removed isLoadingMainFrame. It's not better than
calling frame().isMainFrame() directly.

* page/Frame.cpp:
(Web...