Add <meta viewport> support to the preloader

Source/core/html/parser/HTMLPreloadScanner.cpp

Index: Source/core/html/parser/HTMLPreloadScanner.cpp
diff --git a/Source/core/html/parser/HTMLPreloadScanner.cpp b/Source/core/html/parser/HTMLPreloadScanner.cpp
index 0411f97df82f3335bfeeecb083715da8ae5cc825..6e871291f968a3b378b4e73cb375bbc3efd290e1 100644
--- a/Source/core/html/parser/HTMLPreloadScanner.cpp
+++ b/Source/core/html/parser/HTMLPreloadScanner.cpp
@@ -33,7 +33,9 @@
 #include "core/css/MediaList.h"
 #include "core/css/MediaQueryEvaluator.h"
 #include "core/css/MediaValues.h"
+#include "core/css/MediaValuesCached.h"
 #include "core/css/parser/SizesAttributeParser.h"
+#include "core/html/HTMLMetaElement.h"
 #include "core/html/LinkRelAttribute.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/html/parser/HTMLSrcsetParser.h"
@@ -117,6 +119,7 @@ public:
         , m_allowCredentials(DoNotAllowStoredCredentials)
         , m_mediaValues(mediaValues)
     {
+        ASSERT(m_mediaValues->isCached());
         if (match(m_tagImpl, imgTag)
             || match(m_tagImpl, sourceTag)) {
             m_sourceSize = SizesAttributeParser(m_mediaValues, String()).length();
@@ -384,7 +387,7 @@ private:
     RefPtr<MediaValues> m_mediaValues;
 };
 
-TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<MediaValues> mediaValues)
+TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<MediaValues> mediaValues, const Length& defaultViewportMinWidth, bool viewportMetaZeroValuesQuirk)
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_inPicture(false)
@@ -392,6 +395,8 @@ TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<Med
     , m_isCSPEnabled(false)
     , m_templateCount(0)
     , m_mediaValues(mediaValues)
+    , m_defaultViewportMinWidth(defaultViewportMinWidth)
+    , m_viewportZeroMetaQuirk(viewportMetaZeroValuesQuirk)
 {
 }
 
@@ -493,6 +498,20 @@ void TokenPreloadScanner::scanCommon(const Token& token, const SegmentedString&
                 m_isCSPEnabled = true;
                 return;
             }
+            const typename Token::Attribute* nameAttribute = token.getAttributeItem(nameAttr);
+            if (nameAttribute && equalIgnoringCase(String(nameAttribute->value), "viewport")) {
+                const typename Token::Attribute* contentAttribute = token.getAttributeItem(contentAttr);
+
+                if (contentAttribute) {
+                    ViewportDescription description(ViewportDescription::ViewportMeta);
+                    HTMLMetaElement::getViewportDescriptionFromContentAttribute(String(contentAttribute->value), description, nullptr, m_viewportZeroMetaQuirk);
+                    FloatSize initialViewport(m_mediaValues->viewportHeight(), m_mediaValues->viewportWidth());
+                    PageScaleConstraints constraints = description.resolve(initialViewport, m_defaultViewportMinWidth);
+                    MediaValuesCached* cachedMediaValues = static_cast<MediaValuesCached*>(m_mediaValues.get());
+                    cachedMediaValues->setViewportHeight(constraints.layoutSize.height());
+                    cachedMediaValues->setViewportWidth(constraints.layoutSize.width());
+                }
+            }
         }
 
         if (RuntimeEnabledFeatures::pictureEnabled() && (match(tagImpl, pictureTag))) {
@@ -526,8 +545,8 @@ void TokenPreloadScanner::updatePredictedBaseURL(const Token& token)
     }
 }
 
-HTMLPreloadScanner::HTMLPreloadScanner(const HTMLParserOptions& options, const KURL& documentURL, PassRefPtr<MediaValues> mediaValues)
-    : m_scanner(documentURL, mediaValues)
+HTMLPreloadScanner::HTMLPreloadScanner(const HTMLParserOptions& options, const KURL& documentURL, PassRefPtr<MediaValues> mediaValues, const Length& defaultViewportMinWidth, bool viewportMetaZeroValuesQuirk)
+    : m_scanner(documentURL, mediaValues, defaultViewportMinWidth, viewportMetaZeroValuesQuirk)
     , m_tokenizer(HTMLTokenizer::create(options))
 {
 }