Fullscreen mode on mlb.com shows white letterboxing when video aspect…

… ratio does not match screen

https://bugs.webkit.org/show_bug.cgi?id=217060
<rdar://problem/68936043>

Reviewed by Darin Adler.

Add a Quirk which sets the background color of fullscreen elements on mlb.com to black.

* page/Quirks.cpp:
(WebCore::Quirks::needsBlackFullscreenBackgroundQuirk const):
* page/Quirks.h:
* style/UserAgentStyle.cpp:
(WebCore::Style::UserAgentStyle::ensureDefaultStyleSheetsForElement):


Canonical link: https://commits.webkit.org/229894@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@267773 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,19 @@
+2020-09-29  Jer Noble  <jer.noble@apple.com>
+
+        Fullscreen mode on mlb.com shows white letterboxing when video aspect ratio does not match screen
+        https://bugs.webkit.org/show_bug.cgi?id=217060
+        <rdar://problem/68936043>
+
+        Reviewed by Darin Adler.
+
+        Add a Quirk which sets the background color of fullscreen elements on mlb.com to black.
+
+        * page/Quirks.cpp:
+        (WebCore::Quirks::needsBlackFullscreenBackgroundQuirk const):
+        * page/Quirks.h:
+        * style/UserAgentStyle.cpp:
+        (WebCore::Style::UserAgentStyle::ensureDefaultStyleSheetsForElement):
+
 2020-09-29  Peng Liu  <peng.liu6@apple.com>
 
         [Media in GPU Process] Use VideoLayerManager to manage layers of MediaPlayerPrivateRemote

Source/WebCore/page/Quirks.cpp

@@ -1071,4 +1071,19 @@ bool Quirks::needsAkamaiMediaPlayerQuirk(const HTMLVideoElement& element) const
 #endif
 }
 
+bool Quirks::needsBlackFullscreenBackgroundQuirk() const
+{
+    // MLB.com sets a black background-color on the :backdrop pseudo element, which WebKit does not yet support. This
+    // quirk can be removed once support for :backdrop psedue element is added.
+    if (!needsQuirks())
+        return false;
+
+    if (!m_needsBlackFullscreenBackgroundQuirk) {
+        auto host = m_document->topDocument().url().host();
+        m_needsBlackFullscreenBackgroundQuirk = equalLettersIgnoringASCIICase(host, "mlb.com") || host.endsWithIgnoringASCIICase(".mlb.com");
+    }
+
+    return *m_needsBlackFullscreenBackgroundQuirk;
+}
+
 }

Source/WebCore/page/Quirks.h

@@ -119,6 +119,8 @@ class Quirks {
 
     bool needsAkamaiMediaPlayerQuirk(const HTMLVideoElement&) const;
 
+    bool needsBlackFullscreenBackgroundQuirk() const;
+
 private:
     bool needsQuirks() const;
 
@@ -149,6 +151,7 @@ class Quirks {
     mutable Optional<bool> m_shouldBypassAsyncScriptDeferring;
     mutable Optional<bool> m_needsVP9FullRangeFlagQuirk;
     mutable Optional<bool> m_needsHDRPixelDepthQuirk;
+    mutable Optional<bool> m_needsBlackFullscreenBackgroundQuirk;
 };
 
 }

Source/WebCore/style/UserAgentStyle.cpp

@@ -289,6 +289,8 @@ void UserAgentStyle::ensureDefaultStyleSheetsForElement(const Element& element)
         StringBuilder fullscreenRules;
         fullscreenRules.appendCharacters(fullscreenUserAgentStyleSheet, sizeof(fullscreenUserAgentStyleSheet));
         fullscreenRules.append(RenderTheme::singleton().extraFullScreenStyleSheet());
+        if (element.document().quirks().needsBlackFullscreenBackgroundQuirk())
+            fullscreenRules.append(":-webkit-full-screen { background-color: black; }"_s);
         fullscreenStyleSheet = parseUASheet(fullscreenRules.toString());
         addToDefaultStyle(*fullscreenStyleSheet);
     }