--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1521,17 +1521,17 @@ Element::BindToTree(nsIDocument* aDocume
     //    aDocument->BindingManager()->ChangeDocumentFor(this, nullptr,
     //                                                   aDocument);
 
     // We no longer need to track the subtree pointer (and in fact we'll assert
     // if we do this any later).
     ClearSubtreeRootPointer();
 
     // Being added to a document.
-    SetInDocument();
+    SetIsInDocument();
 
     // Unset this flag since we now really are in a document.
     UnsetFlags(NODE_FORCE_XBL_BINDINGS |
                // And clear the lazy frame construction bits.
                NODE_NEEDS_FRAME | NODE_DESCENDANTS_NEED_FRAMES |
                // And the restyle bits
                ELEMENT_ALL_RESTYLE_FLAGS);
   } else if (IsInShadowTree()) {

--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -1445,16 +1445,23 @@ inline mozilla::dom::Element* nsINode::A
 }
 
 inline const mozilla::dom::Element* nsINode::AsElement() const
 {
   MOZ_ASSERT(IsElement());
   return static_cast<const mozilla::dom::Element*>(this);
 }
 
+inline void nsINode::UnsetRestyleFlagsIfGecko()
+{
+  if (IsElement() && !IsStyledByServo()) {
+    UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
+  }
+}
+
 /**
  * Macros to implement Clone(). _elementName is the class for which to implement
  * Clone.
  */
 #define NS_IMPL_ELEMENT_CLONE(_elementName)                                 \
 nsresult                                                                    \
 _elementName::Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const \
 {                                                                           \

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -1455,17 +1455,20 @@ nsIDocument::nsIDocument()
     mFontFaceSetDirty(true),
     mGetUserFontSetCalled(false),
     mPostedFlushUserFontSet(false),
     mPartID(0),
     mDidFireDOMContentLoaded(true),
     mHasScrollLinkedEffect(false),
     mUserHasInteracted(false)
 {
-  SetInDocument();
+  SetIsDocument();
+  if (IsStyledByServo()) {
+    SetFlags(NODE_IS_DIRTY_FOR_SERVO | NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO);
+  }
 
   PR_INIT_CLIST(&mDOMMediaQueryLists);
 }
 
 // NOTE! nsDocument::operator new() zeroes out all members, so don't
 // bother initializing members to 0.
 
 nsDocument::nsDocument(const char* aContentType)

--- a/dom/base/nsGenericDOMDataNode.cpp
+++ b/dom/base/nsGenericDOMDataNode.cpp
@@ -306,17 +306,17 @@ nsGenericDOMDataNode::SetTextInternal(ui
     nsContentUtils::HasMutationListeners(this,
       NS_EVENT_BITS_MUTATION_CHARACTERDATAMODIFIED,
       this);
 
   nsCOMPtr<nsIAtom> oldValue;
   if (haveMutationListeners) {
     oldValue = GetCurrentValueAtom();
   }
-    
+
   if (aNotify) {
     CharacterDataChangeInfo info = {
       aOffset == textLength,
       aOffset,
       endOffset,
       aLength,
       aDetails
     };
@@ -479,17 +479,17 @@ nsGenericDOMDataNode::BindToTree(nsIDocu
                   "Already have a parent.  Unbind first!");
   NS_PRECONDITION(!GetBindingParent() ||
                   aBindingParent == GetBindingParent() ||
                   (!aBindingParent && aParent &&
                    aParent->GetBindingParent() == GetBindingParent()),
                   "Already have a binding parent.  Unbind first!");
   NS_PRECONDITION(aBindingParent != this,
                   "Content must not be its own binding parent");
-  NS_PRECONDITION(!IsRootOfNativeAnonymousSubtree() || 
+  NS_PRECONDITION(!IsRootOfNativeAnonymousSubtree() ||
                   aBindingParent == aParent,
                   "Native anonymous content must have its parent as its "
                   "own binding parent");
 
   if (!aBindingParent && aParent) {
     aBindingParent = aParent->GetBindingParent();
   }
 
@@ -535,17 +535,17 @@ nsGenericDOMDataNode::BindToTree(nsIDocu
 
   // Set document
   if (aDocument) {
     // We no longer need to track the subtree pointer (and in fact we'll assert
     // if we do this any later).
     ClearSubtreeRootPointer();
 
     // XXX See the comment in Element::BindToTree
-    SetInDocument();
+    SetIsInDocument();
     if (mText.IsBidi()) {
       aDocument->SetBidiEnabled();
     }
     // Clear the lazy frame construction bits.
     UnsetFlags(NODE_NEEDS_FRAME | NODE_DESCENDANTS_NEED_FRAMES);
   } else if (!IsInShadowTree()) {
     // If we're not in the doc and not in a shadow tree,
     // update our subtree pointer.
@@ -800,17 +800,17 @@ nsGenericDOMDataNode::SaveSubtreeState()
 #ifdef DEBUG
 void
 nsGenericDOMDataNode::List(FILE* out, int32_t aIndent) const
 {
 }
 
 void
 nsGenericDOMDataNode::DumpContent(FILE* out, int32_t aIndent,
-                                  bool aDumpAll) const 
+                                  bool aDumpAll) const
 {
 }
 #endif
 
 bool
 nsGenericDOMDataNode::IsLink(nsIURI** aURI) const
 {
   *aURI = nullptr;

--- a/dom/base/nsINode.h
+++ b/dom/base/nsINode.h
@@ -998,16 +998,17 @@ public:
     SetFlags(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO);
   }
 
   inline void SetIsDirtyAndHasDirtyDescendantsForServo() {
     MOZ_ASSERT(IsStyledByServo());
     SetFlags(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO | NODE_IS_DIRTY_FOR_SERVO);
   }
 
+  inline void UnsetRestyleFlagsIfGecko();
 
   /**
    * Adds a mutation observer to be notified when this node, or any of its
    * descendants, are modified. The node will hold a weak reference to the
    * observer, which means that it is the responsibility of the observer to
    * remove itself in case it dies before the node.  If an observer is added
    * while observers are being notified, it may also be notified.  In general,
    * adding observers while inside a notification is not a good idea.  An
@@ -1721,17 +1722,27 @@ public:
 
   void SetMayBeApzAware() { SetBoolFlag(MayBeApzAware); }
   bool NodeMayBeApzAware() const
   {
     return GetBoolFlag(MayBeApzAware);
   }
 protected:
   void SetParentIsContent(bool aValue) { SetBoolFlag(ParentIsContent, aValue); }
-  void SetInDocument() { SetBoolFlag(IsInDocument); }
+  /**
+   * This is a special case of SetIsInDocument used to special-case it for the
+   * document constructor (which can't do the IsStyledByServo() check).
+   */
+  void SetIsDocument() { SetBoolFlag(IsInDocument); }
+  void SetIsInDocument() {
+    if (IsStyledByServo()) {
+      SetIsDirtyAndHasDirtyDescendantsForServo();
+    }
+    SetBoolFlag(IsInDocument);
+  }
   void SetNodeIsContent() { SetBoolFlag(NodeIsContent); }
   void ClearInDocument() { ClearBoolFlag(IsInDocument); }
   void SetIsElement() { SetBoolFlag(NodeIsElement); }
   void SetHasID() { SetBoolFlag(ElementHasID); }
   void ClearHasID() { ClearBoolFlag(ElementHasID); }
   void SetMayHaveStyle() { SetBoolFlag(ElementMayHaveStyle); }
   void SetHasName() { SetBoolFlag(ElementHasName); }
   void ClearHasName() { ClearBoolFlag(ElementHasName); }
@@ -2053,18 +2064,18 @@ public:
     return mServoNodeData;
 #else
     MOZ_CRASH("Accessing servo node data in non-stylo build");
 #endif
   }
 
   void SetServoNodeData(ServoNodeData* aData) {
 #ifdef MOZ_STYLO
-  MOZ_ASSERT(!mServoNodeData);
-  mServoNodeData = aData;
+    MOZ_ASSERT(!mServoNodeData);
+    mServoNodeData = aData;
 #else
     MOZ_CRASH("Setting servo node data in non-stylo build");
 #endif
   }
 
 protected:
   static bool Traverse(nsINode *tmp, nsCycleCollectionTraversalCallback &cb);
   static void Unlink(nsINode *tmp);

--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -1975,17 +1975,17 @@ nsCSSFrameConstructor::GetParentType(nsI
   if (aFrameType == nsGkAtoms::tableColGroupFrame) {
     return eTypeColGroup;
   }
   if (aFrameType == nsGkAtoms::rubyBaseContainerFrame) {
     return eTypeRubyBaseContainer;
   }
   if (aFrameType == nsGkAtoms::rubyTextContainerFrame) {
     return eTypeRubyTextContainer;
-  } 
+  }
   if (aFrameType == nsGkAtoms::rubyFrame) {
     return eTypeRuby;
   }
 
   return eTypeBlock;
 }
 
 static nsContainerFrame*
@@ -2425,17 +2425,17 @@ nsCSSFrameConstructor::ConstructDocEleme
     state.mPresShell->CaptureHistoryState(getter_AddRefs(mTempFrameTreeState));
 
   // Make sure that we'll handle restyles for this document element in
   // the future.  We need this, because the document element might
   // have stale restyle bits from a previous frame constructor for
   // this document.  Unlike in AddFrameConstructionItems, it's safe to
   // unset all element restyle flags, since we don't have any
   // siblings.
-  aDocElement->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
+  aDocElement->UnsetRestyleFlagsIfGecko();
 
   // --------- CREATE AREA OR BOX FRAME -------
   // FIXME: Should this use ResolveStyleContext?  (The calls in this
   // function are the only case in nsCSSFrameConstructor where we don't
   // do so for the construction of a style context for an element.)
   RefPtr<nsStyleContext> styleContext;
   styleContext = mPresShell->StyleSet()->ResolveStyleFor(aDocElement,
                                                          nullptr);
@@ -4135,17 +4135,17 @@ nsCSSFrameConstructor::CreateAnonymousFr
     if (newFrame) {
       NS_ASSERTION(content->GetPrimaryFrame(),
                    "Content must have a primary frame now");
       newFrame->AddStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT);
       aChildItems.AddChild(newFrame);
     } else {
       FrameConstructionItemList items;
       {
-        // Skip parent display based style-fixup during our 
+        // Skip parent display based style-fixup during our
         // AddFrameConstructionItems() call:
         TreeMatchContext::AutoParentDisplayBasedStyleFixupSkipper
           parentDisplayBasedStyleFixupSkipper(aState.mTreeMatchContext);
 
         AddFrameConstructionItems(aState, content, true, insertion, items);
       }
       ConstructFramesFromItemList(aState, items, aParentFrame, aChildItems);
     }
@@ -5508,17 +5508,17 @@ nsCSSFrameConstructor::AddPageBreakItem(
 }
 
 bool
 nsCSSFrameConstructor::ShouldCreateItemsForChild(nsFrameConstructorState& aState,
                                                  nsIContent* aContent,
                                                  nsContainerFrame* aParentFrame)
 {
   aContent->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
-  if (aContent->IsElement()) {
+  if (aContent->IsElement() && !aContent->IsStyledByServo()) {
     // We can't just remove our pending restyle flags, since we may
     // have restyle-later-siblings set on us.  But we _can_ remove the
     // "is possible restyle root" flags, and need to.  Otherwise we can
     // end up with stale such flags (e.g. if we used to have a
     // display:none parent when our last restyle was posted and
     // processed and now no longer do).
     aContent->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS &
                          ~ELEMENT_PENDING_RESTYLE_FLAGS);
@@ -9751,17 +9751,17 @@ nsCSSFrameConstructor::sPseudoParentData
   { // Ruby
     FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT |
                 FCDATA_USE_CHILD_ITEMS |
                 FCDATA_SKIP_FRAMESET,
                 NS_NewRubyFrame),
     &nsCSSAnonBoxes::ruby
   },
   { // Ruby Base
-    FCDATA_DECL(FCDATA_USE_CHILD_ITEMS | 
+    FCDATA_DECL(FCDATA_USE_CHILD_ITEMS |
                 FCDATA_IS_LINE_PARTICIPANT |
                 FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRubyBaseContainer) |
                 FCDATA_SKIP_FRAMESET,
                 NS_NewRubyBaseFrame),
     &nsCSSAnonBoxes::rubyBase
   },
   { // Ruby Base Container
     FCDATA_DECL(FCDATA_USE_CHILD_ITEMS |
@@ -10321,17 +10321,17 @@ nsCSSFrameConstructor::CreateNeededPseud
         break;
       case eTypeTable:
         // Either colgroup or rowgroup, depending on what we're grouping.
         wrapperType = groupingParentType == eTypeColGroup ?
           eTypeColGroup : eTypeRowGroup;
         break;
       case eTypeColGroup:
         MOZ_CRASH("Colgroups should be suppresing non-col child items");
-      default: 
+      default:
         NS_ASSERTION(ourParentType == eTypeBlock, "Unrecognized parent type");
         if (IsRubyParentType(groupingParentType)) {
           wrapperType = eTypeRuby;
         } else {
           NS_ASSERTION(IsTableParentType(groupingParentType),
                        "groupingParentType should be either Ruby or table");
           wrapperType = eTypeTable;
         }
@@ -10537,23 +10537,26 @@ nsCSSFrameConstructor::AddFCItemsForAnon
     nsIContent* content = aAnonymousItems[i].mContent;
 #ifdef DEBUG
     nsIAnonymousContentCreator* creator = do_QueryFrame(aFrame);
     NS_ASSERTION(!creator || !creator->CreateFrameFor(content),
                  "If you need to use CreateFrameFor, you need to call "
                  "CreateAnonymousFrames manually and not follow the standard "
                  "ProcessChildren() codepath for this frame");
 #endif
+    // Anything restyled by servo should already have the style data.
+    MOZ_ASSERT_IF(content->IsStyledByServo(), !!content->GetServoNodeData());
+    // Gecko-styled nodes should have no pending restyle flags.
+    MOZ_ASSERT_IF(!content->IsStyledByServo(),
+                  !content->IsElement() ||
+                  !(content->GetFlags() & ELEMENT_ALL_RESTYLE_FLAGS));
     // Assert some things about this content
     MOZ_ASSERT(!(content->GetFlags() &
                  (NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME)),
                "Should not be marked as needing frames");
-    MOZ_ASSERT(!content->IsElement() ||
-               !(content->GetFlags() & ELEMENT_ALL_RESTYLE_FLAGS),
-               "Should have no pending restyle flags");
     MOZ_ASSERT(!content->GetPrimaryFrame(),
                "Should have no existing frame");
     MOZ_ASSERT(!content->IsNodeOfType(nsINode::eCOMMENT) &&
                !content->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION),
                "Why is someone creating garbage anonymous content");
 
     RefPtr<nsStyleContext> styleContext;
     TreeMatchContext::AutoParentDisplayBasedStyleFixupSkipper
@@ -10691,19 +10694,17 @@ nsCSSFrameConstructor::ProcessChildren(n
           ancestorPusher.PushAncestorAndStyleScope(parent->AsElement());
         } else {
           ancestorPusher.PushStyleScope(parent->AsElement());
         }
       }
 
       // Frame construction item construction should not post
       // restyles, so removing restyle flags here is safe.
-      if (child->IsElement()) {
-        child->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
-      }
+      child->UnsetRestyleFlagsIfGecko();
       if (addChildItems) {
         AddFrameConstructionItems(aState, child, iter.XBLInvolved(), insertion,
                                   itemsToConstruct);
       } else {
         ClearLazyBits(child, child->GetNextSibling());
       }
     }
     itemsToConstruct.SetParentHasNoXBLChildren(!iter.XBLInvolved());
@@ -12003,23 +12004,22 @@ nsCSSFrameConstructor::BuildInlineChildI
       // Manually check for comments/PIs, since we don't have a frame to pass to
       // AddFrameConstructionItems.  We know our parent is a non-replaced inline,
       // so there is no need to do the NeedFrameFor check.
       content->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
       if (content->IsNodeOfType(nsINode::eCOMMENT) ||
           content->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION)) {
         continue;
       }
-      if (content->IsElement()) {
-        // See comment explaining why we need to remove the "is possible
-        // restyle root" flags in AddFrameConstructionItems.  But note
-        // that we can remove all restyle flags, just like in
-        // ProcessChildren and for the same reason.
-        content->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
-      }
+
+      // See comment explaining why we need to remove the "is possible
+      // restyle root" flags in AddFrameConstructionItems.  But note
+      // that we can remove all restyle flags, just like in
+      // ProcessChildren and for the same reason.
+      content->UnsetRestyleFlagsIfGecko();
 
       RefPtr<nsStyleContext> childContext =
         ResolveStyleContext(parentStyleContext, content, &aState);
 
       AddFrameConstructionItemsInternal(aState, content, nullptr,
                                         content->NodeInfo()->NameAtom(),
                                         content->GetNameSpaceID(),
                                         iter.XBLInvolved(), childContext,

--- a/layout/generic/nsFrameSetFrame.cpp
+++ b/layout/generic/nsFrameSetFrame.cpp
@@ -274,29 +274,25 @@ nsHTMLFramesetFrame::Init(nsIContent*   
 
   for (uint32_t childX = 0; childX < numChildren; childX++) {
     if (mChildCount == numCells) { // we have more <frame> or <frameset> than cells
       // Clear the lazy bits in the remaining children.  Also clear
       // the restyle flags, like nsCSSFrameConstructor::ProcessChildren does.
       for (uint32_t i = childX; i < numChildren; i++) {
         nsIContent *child = mContent->GetChildAt(i);
         child->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
-        if (child->IsElement()) {
-          child->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
-        }
+        child->UnsetRestyleFlagsIfGecko();
       }
       break;
     }
     nsIContent *child = mContent->GetChildAt(childX);
     child->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
     // Also clear the restyle flags in the child like
     // nsCSSFrameConstructor::ProcessChildren does.
-    if (child->IsElement()) {
-      child->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
-    }
+    child->UnsetRestyleFlagsIfGecko();
 
     // IMPORTANT: This must match the conditions in
     // nsCSSFrameConstructor::ContentAppended/Inserted/Removed
     if (!child->IsHTMLElement())
       continue;
 
     if (child->IsAnyOfHTMLElements(nsGkAtoms::frameset, nsGkAtoms::frame)) {
       RefPtr<nsStyleContext> kidSC;
@@ -637,22 +633,22 @@ nsresult nsHTMLFramesetFrame::HandleEven
                                            nsEventStatus* aEventStatus)
 {
   NS_ENSURE_ARG_POINTER(aEventStatus);
   if (mDragger) {
     // the nsFramesetBorderFrame has captured NS_MOUSE_DOWN
     switch (aEvent->mMessage) {
       case eMouseMove:
         MouseDrag(aPresContext, aEvent);
-	      break;
+        break;
       case eMouseUp:
         if (aEvent->AsMouseEvent()->button == WidgetMouseEvent::eLeftButton) {
           EndMouseDrag(aPresContext);
         }
-	      break;
+        break;
       default:
         break;
     }
     *aEventStatus = nsEventStatus_eConsumeNoDefault;
   } else {
     *aEventStatus = nsEventStatus_eIgnore;
   }
   return NS_OK;

--- a/layout/style/ServoBindings.cpp
+++ b/layout/style/ServoBindings.cpp
@@ -159,16 +159,35 @@ Gecko_Namespace(RawGeckoElement* aElemen
 
 nsIAtom*
 Gecko_GetElementId(RawGeckoElement* aElement)
 {
   const nsAttrValue* attr = aElement->GetParsedAttr(nsGkAtoms::id);
   return attr ? attr->GetAtomValue() : nullptr;
 }
 
+// Dirtiness tracking.
+uint32_t
+Gecko_GetNodeFlags(RawGeckoNode* aNode)
+{
+  return aNode->GetFlags();
+}
+
+void
+Gecko_SetNodeFlags(RawGeckoNode* aNode, uint32_t aFlags)
+{
+  aNode->SetFlags(aFlags);
+}
+
+void
+Gecko_UnsetNodeFlags(RawGeckoNode* aNode, uint32_t aFlags)
+{
+  aNode->UnsetFlags(aFlags);
+}
+
 template<class MatchFn>
 bool
 DoMatch(RawGeckoElement* aElement, nsIAtom* aNS, nsIAtom* aName, MatchFn aMatch)
 {
   if (aNS) {
     int32_t ns = nsContentUtils::NameSpaceManager()->GetNameSpaceID(aNS);
     NS_ENSURE_TRUE(ns != kNameSpaceID_Unknown, false);
     const nsAttrValue* value = aElement->GetParsedAttr(aName, ns);

--- a/layout/style/ServoBindings.h
+++ b/layout/style/ServoBindings.h
@@ -171,16 +171,21 @@ NS_DECL_HOLDER_FFI_REFCOUNTING(nsIURI, U
 // Display style.
 void Gecko_SetMozBinding(nsStyleDisplay* style_struct,
                          const uint8_t* string_bytes, uint32_t string_length,
                          ThreadSafeURIHolder* base_uri,
                          ThreadSafeURIHolder* referrer,
                          ThreadSafePrincipalHolder* principal);
 void Gecko_CopyMozBindingFrom(nsStyleDisplay* des, const nsStyleDisplay* src);
 
+// Dirtiness tracking.
+uint32_t Gecko_GetNodeFlags(RawGeckoNode* node);
+void Gecko_SetNodeFlags(RawGeckoNode* node, uint32_t flags);
+void Gecko_UnsetNodeFlags(RawGeckoNode* node, uint32_t flags);
+
 // Styleset and Stylesheet management.
 //
 // TODO: Make these return already_AddRefed and UniquePtr when the binding
 // generator is smart enough to handle them.
 RawServoStyleSheet* Servo_StylesheetFromUTF8Bytes(
     const uint8_t* bytes, uint32_t length,
     mozilla::css::SheetParsingMode parsing_mode,
     ThreadSafeURIHolder* base,