Do not block painting for in-body CSS

third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp

 /*
  * Copyright (C) 2000 Peter Kelly (pmk@post.com)
  * Copyright (C) 2006, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 23 matching lines @@
 #include "core/xml/DocumentXSLT.h"
 #include "core/xml/XSLStyleSheet.h"
 #include "core/xml/parser/XMLDocumentParser.h" // for parseAttributes()
 
 namespace blink {
 
 inline ProcessingInstruction::ProcessingInstruction(Document& document, const String& target, const String& data)
     : CharacterData(document, data, CreateOther)
     , m_target(target)
     , m_loading(false)
+    , m_beforeBody(false)
     , m_alternate(false)
     , m_isCSS(false)
     , m_isXSL(false)
     , m_listenerForXSLT(nullptr)
 {
 }
 
 ProcessingInstruction* ProcessingInstruction::create(Document& document, const String& target, const String& data)
 {
     return new ProcessingInstruction(document, target, data);
@@ skipping 104 matching lines @@
     if (m_isXSL) {
         if (RuntimeEnabledFeatures::xsltEnabled())
             resource = XSLStyleSheetResource::fetch(request, document().fetcher());
     } else {
         request.setCharset(charset.isEmpty() ? document().characterSet() : charset);
         resource = CSSStyleSheetResource::fetch(request, document().fetcher());
     }
 
     if (resource) {
         m_loading = true;
-        if (!m_isXSL)
-            document().styleEngine().addPendingSheet();
+        if (!m_isXSL) {
+            m_beforeBody = m_beforeBody || !document().body();
+            document().styleEngine().addPendingSheet(m_beforeBody);
+        }
         setResource(resource);
     }
 }
 
 bool ProcessingInstruction::isLoading() const
 {
     if (m_loading)
         return true;
     if (!m_sheet)
         return false;
     return m_sheet->isLoading();
 }
 
 bool ProcessingInstruction::sheetLoaded()
 {
     if (!isLoading()) {
         if (!DocumentXSLT::sheetLoaded(document(), this))
-            document().styleEngine().removePendingSheet(this);
+            document().styleEngine().removePendingSheet(this, m_beforeBody);
         return true;
     }
     return false;
 }
 
 void ProcessingInstruction::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* sheet)
 {
     if (!inShadowIncludingDocument()) {
         DCHECK(!m_sheet);
         return;
@@ skipping 83 matching lines @@
 
     // If we're in document teardown, then we don't need to do any notification of our sheet's removal.
     if (document().isActive())
         document().styleEngine().setNeedsActiveStyleUpdate(removedSheet, FullStyleUpdate);
 }
 
 void ProcessingInstruction::clearSheet()
 {
     DCHECK(m_sheet);
     if (m_sheet->isLoading())
-        document().styleEngine().removePendingSheet(this);
+        document().styleEngine().removePendingSheet(this, m_beforeBody);
     m_sheet.release()->clearOwnerNode();
 }
 
 DEFINE_TRACE(ProcessingInstruction)
 {
     visitor->trace(m_sheet);
     visitor->trace(m_listenerForXSLT);
     CharacterData::trace(visitor);
     ResourceOwner<StyleSheetResource>::trace(visitor);
 }
 
 } // namespace blink