Current work-in-progress crbug.com/567021

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

Index: third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp
diff --git a/third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp b/third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp
index 0c9eb8c53acd5243a3f0774d6857e3dfc482e3b9..38d47f18d9575d6e05f87b26722838e2e58470e8 100644
--- a/third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp
+++ b/third_party/WebKit/Source/core/dom/ProcessingInstruction.cpp
@@ -205,6 +205,8 @@ void ProcessingInstruction::setCSSStyleSheet(const String& href, const KURL& bas
     CSSStyleSheet* cssSheet = CSSStyleSheet::create(newSheet, this);
     cssSheet->setDisabled(m_alternate);
     cssSheet->setTitle(m_title);
+    if (!m_alternate && !m_title.isEmpty())
+        document().styleEngine().setPreferredStylesheetSetNameIfNotSet(m_title);
     cssSheet->setMediaQueries(MediaQuerySet::create(m_media));
 
     m_sheet = cssSheet;
@@ -270,18 +272,14 @@ void ProcessingInstruction::removedFrom(ContainerNode* insertionPoint)
     if (!DocumentXSLT::processingInstructionRemovedFromDocument(document(), this))
         document().styleEngine().removeStyleSheetCandidateNode(this);
 
-    StyleSheet* removedSheet = m_sheet;
     if (m_sheet) {
         DCHECK_EQ(m_sheet->ownerNode(), this);
         clearSheet();
+        document().styleEngine().setNeedsActiveStyleUpdate(treeScope());
     }
 
     // No need to remove pending sheets.
     clearResource();
-
-    // 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()