diff --git a/content/base/public/Element.h b/content/base/public/Element.h
index ff71563f9686..16c727128852 100644
--- a/content/base/public/Element.h
+++ b/content/base/public/Element.h
@@ -42,6 +42,41 @@
 
 #include "nsIContent.h"
 
+// Element-specific flags
+enum {
+  // Set if the element has a pending style change.
+  ELEMENT_HAS_PENDING_RESTYLE     = (1 << NODE_TYPE_SPECIFIC_BITS_OFFSET),
+
+  // Set if the element is a potential restyle root (that is, has a style
+  // change pending _and_ that style change will attempt to restyle
+  // descendants).
+  ELEMENT_IS_POTENTIAL_RESTYLE_ROOT =
+    (1 << (NODE_TYPE_SPECIFIC_BITS_OFFSET + 1)),
+
+  // Set if the element has a pending animation style change.
+  ELEMENT_HAS_PENDING_ANIMATION_RESTYLE =
+    (1 << (NODE_TYPE_SPECIFIC_BITS_OFFSET + 2)),
+
+  // Set if the element is a potential animation restyle root (that is,
+  // has an animation style change pending _and_ that style change
+  // will attempt to restyle descendants).
+  ELEMENT_IS_POTENTIAL_ANIMATION_RESTYLE_ROOT =
+    (1 << (NODE_TYPE_SPECIFIC_BITS_OFFSET + 3)),
+
+  // All of those bits together, for convenience.
+  ELEMENT_ALL_RESTYLE_FLAGS = ELEMENT_HAS_PENDING_RESTYLE |
+                              ELEMENT_IS_POTENTIAL_RESTYLE_ROOT |
+                              ELEMENT_HAS_PENDING_ANIMATION_RESTYLE |
+                              ELEMENT_IS_POTENTIAL_ANIMATION_RESTYLE_ROOT,
+
+  // Just the HAS_PENDING bits, for convenience
+  ELEMENT_PENDING_RESTYLE_FLAGS = ELEMENT_HAS_PENDING_RESTYLE |
+                                  ELEMENT_HAS_PENDING_ANIMATION_RESTYLE,
+
+  // Remaining bits are for subclasses
+  ELEMENT_TYPE_SPECIFIC_BITS_OFFSET = NODE_TYPE_SPECIFIC_BITS_OFFSET + 4
+};
+
 namespace mozilla {
 namespace dom {
 
diff --git a/content/base/src/nsGenericElement.cpp b/content/base/src/nsGenericElement.cpp
index a5de45755025..0345371f1c4d 100644
--- a/content/base/src/nsGenericElement.cpp
+++ b/content/base/src/nsGenericElement.cpp
@@ -2882,7 +2882,9 @@ nsGenericElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
     // 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);
+               NODE_NEEDS_FRAME | NODE_DESCENDANTS_NEED_FRAMES |
+               // And the restyle bits
+               ELEMENT_ALL_RESTYLE_FLAGS);
   }
 
   // If NODE_FORCE_XBL_BINDINGS was set we might have anonymous children
diff --git a/content/html/content/src/nsGenericHTMLElement.h b/content/html/content/src/nsGenericHTMLElement.h
index 19c893fecca6..ebee3ee0e18f 100644
--- a/content/html/content/src/nsGenericHTMLElement.h
+++ b/content/html/content/src/nsGenericHTMLElement.h
@@ -886,19 +886,19 @@ protected:
 // added ourselves to our mForm.  It's possible to have a non-null mForm, but
 // not have this flag set.  That happens when the form is set via the content
 // sink.
-#define ADDED_TO_FORM (1 << NODE_TYPE_SPECIFIC_BITS_OFFSET)
+#define ADDED_TO_FORM (1 << ELEMENT_TYPE_SPECIFIC_BITS_OFFSET)
 
 // If this flag is set on an nsGenericHTMLFormElement, that means that its form
 // is in the process of being unbound from the tree, and this form element
 // hasn't re-found its form in nsGenericHTMLFormElement::UnbindFromTree yet.
-#define MAYBE_ORPHAN_FORM_ELEMENT (1 << (NODE_TYPE_SPECIFIC_BITS_OFFSET+1))
+#define MAYBE_ORPHAN_FORM_ELEMENT (1 << (ELEMENT_TYPE_SPECIFIC_BITS_OFFSET+1))
 
 // NOTE: I don't think it's possible to have the above two flags set at the
 // same time, so if it becomes an issue we can probably merge them into the
 // same bit.  --bz
 
 // Make sure we have enough space for those bits
-PR_STATIC_ASSERT(NODE_TYPE_SPECIFIC_BITS_OFFSET + 1 < 32);
+PR_STATIC_ASSERT(ELEMENT_TYPE_SPECIFIC_BITS_OFFSET + 1 < 32);
 
 //----------------------------------------------------------------------
 
diff --git a/content/xul/content/src/nsXULElement.h b/content/xul/content/src/nsXULElement.h
index 676f1479ac0a..77212a0c46c8 100644
--- a/content/xul/content/src/nsXULElement.h
+++ b/content/xul/content/src/nsXULElement.h
@@ -449,10 +449,10 @@ public:
 
  */
 
-#define XUL_ELEMENT_TEMPLATE_GENERATED (1 << NODE_TYPE_SPECIFIC_BITS_OFFSET)
+#define XUL_ELEMENT_TEMPLATE_GENERATED (1 << ELEMENT_TYPE_SPECIFIC_BITS_OFFSET)
 
 // Make sure we have space for our bit
-PR_STATIC_ASSERT(NODE_TYPE_SPECIFIC_BITS_OFFSET < 32);
+PR_STATIC_ASSERT(ELEMENT_TYPE_SPECIFIC_BITS_OFFSET < 32);
 
 class nsScriptEventHandlerOwnerTearoff;