[GTK] Fix cmake build when ENABLE_MHTML flag is off

[kiranpradeep]

62443ea

[GTK] Fix cmake build when ENABLE_MHTML flag is off
https://bugs.webkit.org/show_bug.cgi?id=146905

Unreviewed test gardening

ENABLE(MHTML) Preprocessor guards are added to WebKitWebView.cpp.
This approach  is copied from WKPageGetContentsAsMHTMLData() method
in file WKPage.cpp (path: UIProcess/API/C)

* Source/WebKit/UIProcess/API/glib/WebKitWebView.cpp:
(webkit_web_view_save):
(webkit_web_view_save_to_file):

62443ea

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

[webkit-early-warning-system]

EWS run on current version of this PR (hash 62443ea)

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

[mcatanzaro]

Hi, you need to make sure the callback always gets called. What you have now breaks if ENABLE(MHTML) is disabled: the call will never finish.

P.S. This is not a public build option and disabling it is not supported, but whatever, adding two guards is hardly a big deal.

[kiranpradeep]

@mcatanzaro oh private flags - my bad. I was using cmake-gui which did not differentiate what was private flags from public ones. I was trying to build gtk port with just 3 options (Webkit, Webcore, JavascriptCore) enabled (I disabled everything else in cmake-gui). And hit this issue.

I could not test this with minibrowser. So followed what was already in WKPage.cpp line 2673. I am abandoing this PR as it is not expected to be used by public,

[mcatanzaro]

I think cmake-gui should distinguish between ADVANCED options (for developers/experts) vs. user-facing options?

You'll have a real tough time with everything disabled. :)

[mcatanzaro]

I could not test this with minibrowser. So followed what was already in WKPage.cpp line 2673. I am abandoing this PR as it is not expected to be used by public,

You actually found a bug there! The callback should always be executed. Feel free to file a bug report if you want.

[kiranpradeep]

You actually found a bug there! The callback should always be executed. Feel free to file a bug report if you want.

@mcatanzaro Raised 251353. But it feels incomplete info as I could not find info on what should values of WKDataRef/WKErrorRef when callback is invoked (with MHTML off).