Bug 1087460 - Part 1: Make GetComposedDoc() work in UnbindFromTree. r=smaug

dom/base/Element.cpp

@@ -992,6 +992,8 @@ Element::CreateShadowRoot(ErrorResult& aError)
   nsRefPtr<ShadowRoot> shadowRoot = new ShadowRoot(this, nodeInfo.forget(),
                                                    protoBinding);
 
+  shadowRoot->SetIsComposedDocParticipant(IsInComposedDoc());
+
   // Replace the old ShadowRoot with the new one and let the old
   // ShadowRoot know about the younger ShadowRoot because the old
   // ShadowRoot is projected into the younger ShadowRoot's shadow
@@ -1007,6 +1009,8 @@ Element::CreateShadowRoot(ErrorResult& aError)
          child = child->GetNextSibling()) {
       child->UnbindFromTree(true, false);
     }
+
+    olderShadow->SetIsComposedDocParticipant(false);
   }
 
   // xblBinding takes ownership of docInfo.
@@ -1578,6 +1582,7 @@ Element::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
   // Call BindToTree on shadow root children.
   ShadowRoot* shadowRoot = GetShadowRoot();
   if (shadowRoot) {
+    shadowRoot->SetIsComposedDocParticipant(IsInComposedDoc());
     for (nsIContent* child = shadowRoot->GetFirstChild(); child;
          child = child->GetNextSibling()) {
       rv = child->BindToTree(nullptr, shadowRoot,
@@ -1635,8 +1640,7 @@ Element::UnbindFromTree(bool aDeep, bool aNullParent)
 
   // Make sure to unbind this node before doing the kids
   nsIDocument* document =
-    HasFlag(NODE_FORCE_XBL_BINDINGS) || IsInShadowTree() ?
-      OwnerDoc() : GetUncomposedDoc();
+    HasFlag(NODE_FORCE_XBL_BINDINGS) ? OwnerDoc() : GetComposedDoc();
 
   if (aNullParent) {
     if (IsFullScreenAncestor()) {
@@ -1756,6 +1760,8 @@ Element::UnbindFromTree(bool aDeep, bool aNullParent)
          child = child->GetNextSibling()) {
       child->UnbindFromTree(true, false);
     }
+
+    shadowRoot->SetIsComposedDocParticipant(false);
   }
 }
 

dom/base/ShadowRoot.cpp

@@ -67,7 +67,7 @@ ShadowRoot::ShadowRoot(nsIContent* aContent,
                        nsXBLPrototypeBinding* aProtoBinding)
   : DocumentFragment(aNodeInfo), mPoolHost(aContent),
     mProtoBinding(aProtoBinding), mShadowElement(nullptr),
-    mInsertionPointChanged(false)
+    mInsertionPointChanged(false), mIsComposedDocParticipant(false)
 {
   SetHost(aContent);
 

dom/base/ShadowRoot.h

@@ -127,6 +127,12 @@ public:
   Element* Host();
   ShadowRoot* GetOlderShadowRoot() { return mOlderShadow; }
   void StyleSheetChanged();
+
+  bool IsComposedDocParticipant() { return mIsComposedDocParticipant; }
+  void SetIsComposedDocParticipant(bool aIsComposedDocParticipant)
+  {
+    mIsComposedDocParticipant = aIsComposedDocParticipant;
+  }
 protected:
   virtual ~ShadowRoot();
 
@@ -171,6 +177,12 @@ protected:
   // the insertion points. After this flag is set, nodes will be distributed
   // on the next mutation event.
   bool mInsertionPointChanged;
+
+  // Flag to indicate whether the descendants of this shadow root are part of the
+  // composed document. Ideally, we would use a node flag on nodes to
+  // mark whether it is in the composed document, but we have run out of flags
+  // so instead we track it here.
+  bool mIsComposedDocParticipant;
 };
 
 class ShadowRootStyleSheetList : public StyleSheetList

dom/base/nsGenericDOMDataNode.cpp

@@ -113,6 +113,10 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsGenericDOMDataNode)
   nsINode::Unlink(tmp);
 
+  // Clear flag here because unlinking slots will clear the
+  // containing shadow root pointer.
+  tmp->UnsetFlags(NODE_IS_IN_SHADOW_TREE);
+
   nsDataSlots *slots = tmp->GetExistingDataSlots();
   if (slots) {
     slots->Unlink();
@@ -562,8 +566,7 @@ nsGenericDOMDataNode::UnbindFromTree(bool aDeep, bool aNullParent)
              NS_REFRAME_IF_WHITESPACE);
 
   nsIDocument* document =
-    HasFlag(NODE_FORCE_XBL_BINDINGS) || IsInShadowTree() ?
-      OwnerDoc() : GetUncomposedDoc();
+    HasFlag(NODE_FORCE_XBL_BINDINGS) ? OwnerDoc() : GetComposedDoc();
 
   if (aNullParent) {
     if (GetParent()) {

dom/base/nsINode.cpp

@@ -390,17 +390,8 @@ nsINode::GetComposedDocInternal() const
   MOZ_ASSERT(HasFlag(NODE_IS_IN_SHADOW_TREE) && IsContent(),
              "Should only be caled on nodes in the shadow tree.");
 
-  // Cross ShadowRoot boundary.
   ShadowRoot* containingShadow = AsContent()->GetContainingShadow();
-
-  nsIContent* poolHost = containingShadow->GetPoolHost();
-  if (!poolHost) {
-    // This node is in an older shadow root that does not get projected into
-    // an insertion point, thus this node can not be in the composed document.
-    return nullptr;
-  }
-
-  return poolHost->GetComposedDoc();
+  return containingShadow->IsComposedDocParticipant() ?  OwnerDoc() : nullptr;
 }
 
 #ifdef DEBUG

dom/base/nsINode.h

@@ -520,11 +520,9 @@ public:
   }
 
   /**
-   * This method gets the current doc of the node hosting this content
-   * or the current doc of this content if it is not being hosted. This
-   * method walks through ShadowRoot boundaries until it reach the host
-   * that is located in the root of the "tree of trees" (see Shadow DOM
-   * spec) and returns the current doc for that host.
+   * This method returns the owner doc if the node is in the
+   * composed document (as defined in the Shadow DOM spec), otherwise
+   * it returns null.
    */
   nsIDocument* GetComposedDoc() const
   {

dom/html/HTMLShadowElement.cpp

@@ -146,6 +146,8 @@ HTMLShadowElement::BindToTree(nsIDocument* aDocument,
     // Propagate BindToTree calls to projected shadow root children.
     ShadowRoot* projectedShadow = containingShadow->GetOlderShadowRoot();
     if (projectedShadow) {
+      projectedShadow->SetIsComposedDocParticipant(IsInComposedDoc());
+
       for (nsIContent* child = projectedShadow->GetFirstChild(); child;
            child = child->GetNextSibling()) {
         rv = child->BindToTree(nullptr, projectedShadow,
@@ -173,6 +175,8 @@ HTMLShadowElement::UnbindFromTree(bool aDeep, bool aNullParent)
            child = child->GetNextSibling()) {
         child->UnbindFromTree(true, false);
       }
+
+      projectedShadow->SetIsComposedDocParticipant(false);
     }
   }
 

dom/html/HTMLStyleElement.cpp

@@ -157,15 +157,14 @@ void
 HTMLStyleElement::UnbindFromTree(bool aDeep, bool aNullParent)
 {
   nsCOMPtr<nsIDocument> oldDoc = GetUncomposedDoc();
-  nsCOMPtr<nsIDocument> oldComposedDoc = GetComposedDoc();
   ShadowRoot* oldShadow = GetContainingShadow();
 
   nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
 
-  if (GetContainingShadow() && !oldComposedDoc) {
-    // The style is in a shadow tree and was already not
-    // in the composed document. Thus the sheet does not
-    // need to be updated.
+  if (oldShadow && GetContainingShadow()) {
+    // The style is in a shadow tree and is still in the
+    // shadow tree. Thus the sheets in the shadow DOM
+    // do not need to be updated.
     return;
   }