[Lockdown Mode] Disable WebSpeech API (Speech Synthesis)

https://bugs.webkit.org/show_bug.cgi?id=249346
<rdar://problem/103316392>

Reviewed by Chris Dumez.

Disable the speech synthesis portions of the Web Speech API in Lockdown Mode.
(We already disable the Speech Recognition portions).

* Source/WebKit/WebProcess/WebPage/WebPage.cpp:
(WebKit::adjustSettingsForLockdownMode):
* Tools/TestWebKitAPI/Tests/WebKitCocoa/ProcessSwapOnNavigation.mm:

Canonical link: https://commits.webkit.org/257933@main

Source/WebKit/WebProcess/WebPage/WebPage.cpp

@@ -4153,6 +4153,9 @@ static void adjustSettingsForLockdownMode(Settings& settings, const WebPreferenc
     settings.setPictureInPictureAPIEnabled(false);
 #endif
     settings.setSpeechRecognitionEnabled(false);
+#if ENABLE(SPEECH_SYNTHESIS)
+    settings.setSpeechSynthesisAPIEnabled(false);
+#endif
 #if ENABLE(NOTIFICATIONS)
     settings.setNotificationsEnabled(false);
 #endif

Tools/TestWebKitAPI/Tests/WebKitCocoa/ProcessSwapOnNavigation.mm

@@ -7877,6 +7877,9 @@ static void checkSettingsControlledByLockdownMode(WKWebView *webView, ShouldBeEn
     EXPECT_EQ(runJSCheck("!!window.HTMLModelElement"_s), shouldBeEnabled == ShouldBeEnabled::Yes); // AR (Model)
     EXPECT_EQ(runJSCheck("!!window.PictureInPictureEvent"_s), shouldBeEnabled == ShouldBeEnabled::Yes); // Picture in Picture API.
     EXPECT_EQ(runJSCheck("!!window.SpeechRecognitionEvent"_s), shouldBeEnabled == ShouldBeEnabled::Yes); // Speech recognition.
+#if ENABLE(SPEECH_SYNTHESIS)
+    EXPECT_EQ(runJSCheck("!!window.SpeechSynthesisEvent"_s), shouldBeEnabled == ShouldBeEnabled::Yes); // Speech synthesis.
+#endif
 #if ENABLE(NOTIFICATIONS)
     EXPECT_EQ(runJSCheck("!!window.Notification"_s), shouldBeEnabled == ShouldBeEnabled::Yes); // Notification API.
 #endif