Bug 1331322 - Allow tagging of pseudo-implementing native anonymous content with the pseudo type at creation time

* Stop using a node bit for HasExplicitBaseURI
* Move MAY_HAVE_CLASS to mBoolFlags
* Add a flag to indicate that a node is native anonymous content
* Allow tagging of pseudo-implementing native anonymous content with the pseudo type at creation time, and eliminate explicit style contexts in nsIAnonymousContentCreator::ContentInfo

Tag #1375

7 files changed, 64 insertions, 17 deletions

diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 5a92853ae..91a3b63d7 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -166,8 +166,7 @@ nsIContent::DoGetID() const
 const nsAttrValue*
 Element::DoGetClasses() const
 {
-  MOZ_ASSERT(HasFlag(NODE_MAY_HAVE_CLASS), "Unexpected call");
-
+  MOZ_ASSERT(MayHaveClass(), "Unexpected call");
   if (IsSVGElement()) {
     const nsAttrValue* animClass =
       static_cast<const nsSVGElement*>(this)->GetAnimatedClassName();
@@ -2702,7 +2701,7 @@ Element::ParseAttribute(int32_t aNamespaceID,
 {
   if (aNamespaceID == kNameSpaceID_None) {
     if (aAttribute == nsGkAtoms::_class) {
-      SetFlags(NODE_MAY_HAVE_CLASS);
+      SetMayHaveClass();
       // Result should have been preparsed above.
       return true;
     }
diff --git a/dom/base/Element.h b/dom/base/Element.h
index 1b29f0346..8139236aa 100644
--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -591,7 +591,7 @@ public:
    * guaranteed (e.g. we could have class="").
    */
   const nsAttrValue* GetClasses() const {
-    if (HasFlag(NODE_MAY_HAVE_CLASS)) {
+    if (MayHaveClass()) {
       return DoGetClasses();
     }
     return nullptr;
@@ -763,6 +763,25 @@ public:
   already_AddRefed<nsIHTMLCollection>
     GetElementsByClassName(const nsAString& aClassNames);
 
+  CSSPseudoElementType GetPseudoElementType() const {
+    if (!HasProperties()) {
+      return CSSPseudoElementType::NotPseudo;
+    }
+    nsresult rv = NS_OK;
+    auto raw = GetProperty(nsGkAtoms::pseudoProperty, &rv);
+    if (rv == NS_PROPTABLE_PROP_NOT_THERE) {
+      return CSSPseudoElementType::NotPseudo;
+    }
+    return CSSPseudoElementType(reinterpret_cast<uintptr_t>(raw));
+  }
+
+  void SetPseudoElementType(CSSPseudoElementType aPseudo) {
+    static_assert(sizeof(CSSPseudoElementType) <= sizeof(uintptr_t),
+                  "Need to be able to store this in a void*");
+    MOZ_ASSERT(aPseudo != CSSPseudoElementType::NotPseudo);
+    SetProperty(nsGkAtoms::pseudoProperty, reinterpret_cast<void*>(aPseudo));
+  }
+
 private:
   /**
    * Implement the algorithm specified at
diff --git a/dom/base/crashtests/crashtests.list b/dom/base/crashtests/crashtests.list
index 0fb597b30..d8b5e9625 100644
--- a/dom/base/crashtests/crashtests.list
+++ b/dom/base/crashtests/crashtests.list
@@ -193,7 +193,7 @@ load 930250.html
 load 942979.html
 load 973401.html
 load 978646.html
-pref(dom.webcomponents.enabled,true) load 1024428-1.html
+pref(dom.webcomponents.enabled,true) load 1024428-1.html # bug 1340009
 load 1026714.html
 pref(dom.webcomponents.enabled,true) load 1027461-1.html
 pref(dom.webcomponents.enabled,true) load 1029710.html
diff --git a/dom/base/nsGkAtomList.h b/dom/base/nsGkAtomList.h
index 73a3a02b1..c7c1197b1 100644
--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -2162,6 +2162,7 @@ GK_ATOM(lockedStyleStates, "lockedStyleStates")
 GK_ATOM(apzCallbackTransform, "apzCallbackTransform")
 GK_ATOM(restylableAnonymousNode, "restylableAnonymousNode")
 GK_ATOM(paintRequestTime, "PaintRequestTime")
+GK_ATOM(pseudoProperty, "PseudoProperty")  // CSSPseudoElementType
 
 // Languages for lang-specific transforms
 GK_ATOM(Japanese, "ja")
diff --git a/dom/base/nsIContent.h b/dom/base/nsIContent.h
index 52f2ba5b2..ff0c57e8c 100644
--- a/dom/base/nsIContent.h
+++ b/dom/base/nsIContent.h
@@ -193,7 +193,7 @@ public:
   void SetIsNativeAnonymousRoot()
   {
     SetFlags(NODE_IS_ANONYMOUS_ROOT | NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE |
-             NODE_IS_NATIVE_ANONYMOUS_ROOT);
+             NODE_IS_NATIVE_ANONYMOUS_ROOT | NODE_IS_NATIVE_ANONYMOUS);
   }
 
   /**
diff --git a/dom/base/nsINode.cpp b/dom/base/nsINode.cpp
index 0b56f519d..560ded6a9 100644
--- a/dom/base/nsINode.cpp
+++ b/dom/base/nsINode.cpp
@@ -1515,7 +1515,6 @@ nsINode::SetExplicitBaseURI(nsIURI* aURI)
 {
   nsresult rv = SetProperty(nsGkAtoms::baseURIProperty, aURI, ReleaseURI);
   if (NS_SUCCEEDED(rv)) {
-    SetHasExplicitBaseURI();
     NS_ADDREF(aURI);
   }
   return rv;
diff --git a/dom/base/nsINode.h b/dom/base/nsINode.h
index a0d972f80..0f882445f 100644
--- a/dom/base/nsINode.h
+++ b/dom/base/nsINode.h
@@ -126,9 +126,28 @@ enum {
 
   NODE_IS_EDITABLE =                      NODE_FLAG_BIT(7),
 
-  // For all Element nodes, NODE_MAY_HAVE_CLASS is guaranteed to be set if the
-  // node in fact has a class, but may be set even if it doesn't.
-  NODE_MAY_HAVE_CLASS =                   NODE_FLAG_BIT(8),
+  // This node was created by layout as native anonymous content. This
+  // generally corresponds to things created by nsIAnonymousContentCreator,
+  // though there are exceptions (svg:use content does not have this flag
+  // set, and any non-nsIAnonymousContentCreator callers of
+  // SetIsNativeAnonymousRoot also get this flag).
+  //
+  // One very important aspect here is that this node is not transitive over
+  // the subtree (if you want that, use NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE).
+  // If Gecko code somewhere attaches children to a node with this bit set,
+  // the children will not have the bit themselves unless the calling code sets
+  // it explicitly. This means that XBL content bound to NAC doesn't get this
+  // bit, nor do nodes inserted by editor.
+  //
+  // For now, this bit exists primarily to control style inheritance behavior,
+  // since the nodes for which we set it are often used to implement pseudo-
+  // elements, which need to inherit style from a script-visible element.
+  //
+  // A more general principle for this bit might be this: If the node is entirely
+  // a detail of layout, is not script-observable in any way, and other engines
+  // might accomplish the same task with a nodeless layout frame, then the node
+  // should have this bit set.
+  NODE_IS_NATIVE_ANONYMOUS =              NODE_FLAG_BIT(8),
 
   // Whether the node participates in a shadow tree.
   NODE_IS_IN_SHADOW_TREE =                NODE_FLAG_BIT(9),
@@ -1212,6 +1231,15 @@ public:
   }
 
   /**
+   * Returns true if |this| is native anonymous (i.e. created by
+   * nsIAnonymousContentCreator);
+   */
+  bool IsNativeAnonymous() const
+  {
+    return HasFlag(NODE_IS_NATIVE_ANONYMOUS);
+  }
+
+  /**
    * Returns true if |this| or any of its ancestors is native anonymous.
    */
   bool IsInNativeAnonymousSubtree() const
@@ -1343,10 +1371,11 @@ public:
 
 protected:
   nsIURI* GetExplicitBaseURI() const {
-    if (HasExplicitBaseURI()) {
-      return static_cast<nsIURI*>(GetProperty(nsGkAtoms::baseURIProperty));
+    if (!HasProperties()) {
+      return nullptr;
     }
-    return nullptr;
+
+    return static_cast<nsIURI*>(GetProperty(nsGkAtoms::baseURIProperty));
   }
 
 public:
@@ -1549,6 +1578,8 @@ private:
     // cases lie for nsXMLElement, such as when the node has been moved between
     // documents with different id mappings.
     ElementHasID,
+    // Set if the element might have a class.
+    ElementMayHaveClass,
     // Set if the element might have inline style.
     ElementMayHaveStyle,
     // Set if the element has a name attribute set.
@@ -1567,8 +1598,6 @@ private:
     // Maybe set if the node is a root of a subtree
     // which needs to be kept in the purple buffer.
     NodeIsPurpleRoot,
-    // Set if the node has an explicit base URI stored
-    NodeHasExplicitBaseURI,
     // Set if the element has some style states locked
     ElementHasLockedStyleStates,
     // Set if element has pointer locked
@@ -1645,6 +1674,8 @@ public:
     { SetBoolFlag(NodeHasRenderingObservers, aValue); }
   bool IsContent() const { return GetBoolFlag(NodeIsContent); }
   bool HasID() const { return GetBoolFlag(ElementHasID); }
+  bool MayHaveClass() const { return GetBoolFlag(ElementMayHaveClass); }
+  void SetMayHaveClass() { SetBoolFlag(ElementMayHaveClass); }
   bool MayHaveStyle() const { return GetBoolFlag(ElementMayHaveStyle); }
   bool HasName() const { return GetBoolFlag(ElementHasName); }
   bool MayHaveContentEditableAttr() const
@@ -1774,8 +1805,6 @@ protected:
   void ClearHasName() { ClearBoolFlag(ElementHasName); }
   void SetMayHaveContentEditableAttr()
     { SetBoolFlag(ElementMayHaveContentEditableAttr); }
-  bool HasExplicitBaseURI() const { return GetBoolFlag(NodeHasExplicitBaseURI); }
-  void SetHasExplicitBaseURI() { SetBoolFlag(NodeHasExplicitBaseURI); }
   void SetHasLockedStyleStates() { SetBoolFlag(ElementHasLockedStyleStates); }
   void ClearHasLockedStyleStates() { ClearBoolFlag(ElementHasLockedStyleStates); }
   bool HasLockedStyleStates() const