[Quirk] iPadOS: Unable to enter PIN in account linking flow on shopee.sg

https://bugs.webkit.org/show_bug.cgi?id=273864
rdar://127031587

Reviewed by Tim Horton.

Add a quirk to use an *iPhone* user agent on `shopee.sg/payment/account-linking/landing`. Currently,
sending either macOS or (non-desktop-class) iPad user agents cause Shopee to load content that
doesn't work unless the user has a hardware keyboard; namely, the PIN input elements don't actually
use focusable elements at all, and instead rely on receiving hardware keyboard events.

Work around this for now with a site-specific quirk to load an iPhone user agent in this specific
landing page; while the layout doesn't fit very well for an iPad screen, it's at least functional.

* Source/WebCore/page/Quirks.cpp:
(WebCore::Quirks::needsIPadMiniUserAgent):
(WebCore::Quirks::needsIPhoneUserAgent):
(WebCore::Quirks::needsIpadMiniUserAgent): Deleted.
* Source/WebCore/page/Quirks.h:
* Source/WebKit/UIProcess/ios/WebPageProxyIOS.mm:
(WebKit::desktopClassBrowsingRecommendedForRequest):
(WebKit::WebPageProxy::effectiveContentModeAfterAdjustingPolicies):

Canonical link: https://commits.webkit.org/278493@main

Source/WebCore/page/Quirks.cpp

@@ -1707,7 +1707,7 @@ bool Quirks::shouldDisableNavigatorStandaloneQuirk() const
 // FIXME: find the reference radars and/or bugs.webkit.org issues on why these were added in the first place.
 // FIXME: There is no check currently on needsQuirks(), this needs to be fixed so it makes it easier
 // to deactivate them for testing.
-bool Quirks::needsIpadMiniUserAgent(const URL& url)
+bool Quirks::needsIPadMiniUserAgent(const URL& url)
 {
     auto host = url.host();
 
@@ -1787,6 +1787,16 @@ bool Quirks::needsIpadMiniUserAgent(const URL& url)
     return false;
 }
 
+bool Quirks::needsIPhoneUserAgent(const URL& url)
+{
+#if PLATFORM(IOS_FAMILY)
+    if (url.host() == "shopee.sg"_s && url.path() == "/payment/account-linking/landing"_s)
+        return true;
+#else
+    UNUSED_PARAM(url);
+#endif
+    return false;
+}
 
 bool Quirks::shouldIgnorePlaysInlineRequirementQuirk() const
 {

Source/WebCore/page/Quirks.h

@@ -101,7 +101,8 @@ class Quirks {
 
     WEBCORE_EXPORT static void updateStorageAccessUserAgentStringQuirks(HashMap<RegistrableDomain, String>&&);
     WEBCORE_EXPORT String storageAccessUserAgentStringQuirkForDomain(const URL&);
-    WEBCORE_EXPORT static bool needsIpadMiniUserAgent(const URL&);
+    WEBCORE_EXPORT static bool needsIPadMiniUserAgent(const URL&);
+    WEBCORE_EXPORT static bool needsIPhoneUserAgent(const URL&);
 
     bool needsGMailOverflowScrollQuirk() const;
     bool needsYouTubeOverflowScrollQuirk() const;

Source/WebKit/UIProcess/ios/WebPageProxyIOS.mm

@@ -1350,7 +1350,10 @@ static RecommendDesktopClassBrowsingForRequest desktopClassBrowsingRecommendedFo
     // FIXME: This should be additionally gated on site-specific quirks being enabled.
     // See also: <rdar://problem/50035167>.
     // The list of domain names is currently available in Source/WebCore/page/Quirks.cpp
-    if (Quirks::needsIpadMiniUserAgent(request.url()))
+    if (Quirks::needsIPadMiniUserAgent(request.url()))
+        return RecommendDesktopClassBrowsingForRequest::No;
+
+    if (Quirks::needsIPhoneUserAgent(request.url()))
         return RecommendDesktopClassBrowsingForRequest::No;
 
     return RecommendDesktopClassBrowsingForRequest::Auto;
@@ -1430,6 +1433,12 @@ static RecommendDesktopClassBrowsingForRequest desktopClassBrowsingRecommendedFo
         policies.setMediaSourcePolicy(WebsiteMediaSourcePolicy::Enable);
     }
 
+    if (Quirks::needsIPhoneUserAgent(request.url())) {
+        policies.setCustomUserAgent(makeStringByReplacingAll(standardUserAgentWithApplicationName(m_applicationNameForUserAgent), "iPad"_s, "iPhone"_s));
+        policies.setCustomNavigatorPlatform("iPhone"_s);
+        return WebContentMode::Mobile;
+    }
+
     bool useDesktopBrowsingMode = useDesktopClassBrowsing(policies, request);
 
     m_preferFasterClickOverDoubleTap = false;