Read the default min-width value from the UA style sheets

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 9bbc57e15937f157cf554080c4cbd57548f8581a..978eb84ed5d09a7b3dc492fce43a40ec550f1597 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -2855,7 +2855,9 @@ void WebViewImpl::updatePageDefinedViewportConstraints(const ViewportDescription
             || (description.maxWidth.type() == ExtendToZoom && m_pageScaleConstraintsSet.pageDefinedConstraints().initialScale == 1.0f))
             setInitialPageScaleOverride(-1);
     }
-    m_pageScaleConstraintsSet.adjustForAndroidWebViewQuirks(adjustedDescription, m_size, page()->settings().layoutFallbackWidth(), deviceScaleFactor(), settingsImpl()->supportDeprecatedTargetDensityDPI(), page()->settings().wideViewportQuirkEnabled(), page()->settings().useWideViewport(), page()->settings().loadWithOverviewMode(), settingsImpl()->viewportMetaNonUserScalableQuirk());
+
+    Length defaultMinWidth = page()->mainFrame()->document()->viewportDefaultMinWidth();
+    m_pageScaleConstraintsSet.adjustForAndroidWebViewQuirks(adjustedDescription, m_size, defaultMinWidth.intValue(), deviceScaleFactor(), settingsImpl()->supportDeprecatedTargetDensityDPI(), page()->settings().wideViewportQuirkEnabled(), page()->settings().useWideViewport(), page()->settings().loadWithOverviewMode(), settingsImpl()->viewportMetaNonUserScalableQuirk());
     float newInitialScale = m_pageScaleConstraintsSet.pageDefinedConstraints().initialScale;
     if (oldInitialScale != newInitialScale && newInitialScale != -1) {
         m_pageScaleConstraintsSet.setNeedsReset(true);