[webkit-dev] Port-specific Settings

[Simon Fraser]

I've seen a few instances recently where Chromium-specific flags were added to Settings, without any #PLATFORM ifdfefs. So we now have:

Via https://bugs.webkit.org/show_bug.cgi?id=59929:
        void setLegacyAccelerated2dCanvasEnabled(bool);
        bool legacyAccelerated2dCanvasEnabled() const { return m_legacyAcceleratedCanvas2dEnabled; }

Via https://bugs.webkit.org/show_bug.cgi?id=74017:
        void setPerTileDrawingEnabled(bool enabled) { m_perTileDrawingEnabled = enabled; }
        bool perTileDrawingEnabled() const { return m_perTileDrawingEnabled; }

Via https://bugs.webkit.org/show_bug.cgi?id=74513:
        void setPartialSwapEnabled(bool enabled) { m_partialSwapEnabled = enabled; }
        bool partialSwapEnabled() const { return m_partialSwapEnabled; }

"legacyAccelerated2dCanvas", "perTileDrawing" and " partialSwap" are gobbledygook to me. I don't think they belong in cross-platform code, or should at least be behind platform #ifdefs.

Simon