[GStreamer] Minor cleanups in GstMappedFrame class

[philn]

04a4f4a

[GStreamer] Minor cleanups in GstMappedFrame class
https://bugs.webkit.org/show_bug.cgi?id=274312

Reviewed by Xabier Rodriguez-Calvar.

There is no need for a m_isValid boolean attribute because the buffer field on the GstVideoFrame can
be checked instead.

* Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.h:
(WebCore::GstMappedFrame::GstMappedFrame):
(WebCore::GstMappedFrame::~GstMappedFrame):
(WebCore::GstMappedFrame::get):
(WebCore::GstMappedFrame::ComponentData const):
(WebCore::GstMappedFrame::ComponentStride const):
(WebCore::GstMappedFrame::info):
(WebCore::GstMappedFrame::width const):
(WebCore::GstMappedFrame::height const):
(WebCore::GstMappedFrame::format const):
(WebCore::GstMappedFrame::planeData const):
(WebCore::GstMappedFrame::planeStride const):
(WebCore::GstMappedFrame::isValid const):
(WebCore::GstMappedFrame::operator bool const):
(WebCore::GstMappedFrame::operator! const):

Canonical link: https://commits.webkit.org/278992@main

d44ba45

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 wincairo-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	❌ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash d44ba45)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 wincairo-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	❌ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 8fc8288)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	🛠 mac	🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	🛠 ios-sim	🛠 mac-AS-debug	🧪 wpe-wk2	❌ 🧪 wincairo-tests
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	🧪 api-wpe
	🧪 ios-wk2-wpt	🧪 mac-wk1	🛠 wpe-cairo
	🧪 api-ios	✅ 🧪 mac-wk2	🛠 gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	🧪 gtk-wk2
⏳ 🧪 services	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress	🧪 api-gtk
	✅ 🛠 watch
	🛠 watch-sim

[webkit-commit-queue]

Committed 278992@main (04a4f4a): https://commits.webkit.org/278992@main

Reviewed commits have been landed. Closing PR #28708 and removing active labels.