diff --git a/content/base/public/Element.h b/content/base/public/Element.h
index c907f63433e..dc9cc334895 100644
--- a/content/base/public/Element.h
+++ b/content/base/public/Element.h
@@ -38,7 +38,6 @@
 #include "nsEvent.h"
 #include "nsAttrValue.h"
 #include "mozilla/dom/BindingDeclarations.h"
-#include "nsIHTMLCollection.h"
 #include "Units.h"
 
 class nsIDOMEventListener;
@@ -600,36 +599,6 @@ public:
                            ErrorResult& aError);
   already_AddRefed<nsIHTMLCollection>
     GetElementsByClassName(const nsAString& aClassNames);
-  Element* GetFirstElementChild() const;
-  Element* GetLastElementChild() const;
-  Element* GetPreviousElementSibling() const
-  {
-    nsIContent* previousSibling = GetPreviousSibling();
-    while (previousSibling) {
-      if (previousSibling->IsElement()) {
-        return previousSibling->AsElement();
-      }
-      previousSibling = previousSibling->GetPreviousSibling();
-    }
-
-    return nullptr;
-  }
-  Element* GetNextElementSibling() const
-  {
-    nsIContent* nextSibling = GetNextSibling();
-    while (nextSibling) {
-      if (nextSibling->IsElement()) {
-        return nextSibling->AsElement();
-      }
-      nextSibling = nextSibling->GetNextSibling();
-    }
-
-    return nullptr;
-  }
-  uint32_t ChildElementCount()
-  {
-    return Children()->Length();
-  }
   bool MozMatchesSelector(const nsAString& aSelector,
                           ErrorResult& aError);
   void SetCapture(bool aRetargetToElement)
diff --git a/content/base/public/FragmentOrElement.h b/content/base/public/FragmentOrElement.h
index 9d5691aaa71..ce4df9199da 100644
--- a/content/base/public/FragmentOrElement.h
+++ b/content/base/public/FragmentOrElement.h
@@ -23,6 +23,7 @@
 #include "nsINodeList.h"                  // base class
 #include "nsIWeakReference.h"             // base class
 #include "nsNodeUtils.h"                  // class member nsNodeUtils::CloneNodeImpl
+#include "nsIHTMLCollection.h"
 
 class ContentUnbinder;
 class nsContentList;
@@ -32,7 +33,6 @@ class nsIControllers;
 class nsICSSDeclaration;
 class nsIDocument;
 class nsDOMStringMap;
-class nsIHTMLCollection;
 class nsINodeInfo;
 class nsIURI;
 
@@ -229,6 +229,10 @@ public:
   NS_IMETHOD WalkContentStyleRules(nsRuleWalker* aRuleWalker) MOZ_OVERRIDE;
 
   nsIHTMLCollection* Children();
+  uint32_t ChildElementCount()
+  {
+    return Children()->Length();
+  }
 
 public:
   /**
diff --git a/content/base/public/nsIDocument.h b/content/base/public/nsIDocument.h
index 50d7ac13a5e..090f82c92d8 100644
--- a/content/base/public/nsIDocument.h
+++ b/content/base/public/nsIDocument.h
@@ -53,6 +53,7 @@ class nsIDOMElement;
 class nsIDOMNodeList;
 class nsIDOMXPathExpression;
 class nsIDOMXPathNSResolver;
+class nsIHTMLCollection;
 class nsILayoutHistoryState;
 class nsIObjectLoadingContent;
 class nsIObserver;
@@ -2120,6 +2121,10 @@ public:
 
   void ObsoleteSheet(const nsAString& aSheetURI, mozilla::ErrorResult& rv);
 
+  // ParentNode
+  nsIHTMLCollection* Children();
+  uint32_t ChildElementCount();
+
   virtual nsHTMLDocument* AsHTMLDocument() { return nullptr; }
 
   virtual JSObject* WrapObject(JSContext *aCx,
@@ -2211,6 +2216,9 @@ protected:
   nsPropertyTable mPropertyTable;
   nsTArray<nsAutoPtr<nsPropertyTable> > mExtraPropertyTables;
 
+  // Our cached .children collection
+  nsCOMPtr<nsIHTMLCollection> mChildrenCollection;
+
   // Compatibility mode
   nsCompatibility mCompatMode;
 
diff --git a/content/base/public/nsINode.h b/content/base/public/nsINode.h
index 1fe886487c5..73f4df0235f 100644
--- a/content/base/public/nsINode.h
+++ b/content/base/public/nsINode.h
@@ -1590,11 +1590,18 @@ public:
     return rv.ErrorCode();
   }
 
+  // ChildNode methods
+  mozilla::dom::Element* GetPreviousElementSibling() const;
+  mozilla::dom::Element* GetNextElementSibling() const;
   /**
    * Remove this node from its parent, if any.
    */
   void Remove();
 
+  // ParentNode methods
+  mozilla::dom::Element* GetFirstElementChild() const;
+  mozilla::dom::Element* GetLastElementChild() const;
+
 protected:
 
   // Override this function to create a custom slots class.
diff --git a/content/base/src/Element.cpp b/content/base/src/Element.cpp
index 86f029d5a96..500d36d3620 100644
--- a/content/base/src/Element.cpp
+++ b/content/base/src/Element.cpp
@@ -416,34 +416,6 @@ Element::WrapObject(JSContext *aCx, JS::Handle<JSObject*> aScope)
   return obj;
 }
 
-Element*
-Element::GetFirstElementChild() const
-{
-  uint32_t i, count = mAttrsAndChildren.ChildCount();
-  for (i = 0; i < count; ++i) {
-    nsIContent* child = mAttrsAndChildren.ChildAt(i);
-    if (child->IsElement()) {
-      return child->AsElement();
-    }
-  }
-  
-  return nullptr;
-}
-
-Element*
-Element::GetLastElementChild() const
-{
-  uint32_t i = mAttrsAndChildren.ChildCount();
-  while (i > 0) {
-    nsIContent* child = mAttrsAndChildren.ChildAt(--i);
-    if (child->IsElement()) {
-      return child->AsElement();
-    }
-  }
-  
-  return nullptr;
-}
-
 nsDOMTokenList*
 Element::GetClassList()
 {
diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index d75693da740..89b5d714e65 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -1793,6 +1793,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(nsDocument)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStateObjectCached)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mUndoManager)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mTemplateContentsOwner)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mChildrenCollection)
 
   // Traverse all our nsCOMArrays.
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStyleSheets)
@@ -1877,6 +1878,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDocument)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mCachedEncoder)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mUndoManager)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mTemplateContentsOwner)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mChildrenCollection)
 
   tmp->mParentDocument = nullptr;
 
@@ -9475,6 +9477,25 @@ nsIDocument::ObsoleteSheet(const nsAString& aSheetURI, ErrorResult& rv)
   }
 }
 
+nsIHTMLCollection*
+nsIDocument::Children()
+{
+  if (!mChildrenCollection) {
+    mChildrenCollection = new nsContentList(this, kNameSpaceID_Wildcard,
+                                            nsGkAtoms::_asterix,
+                                            nsGkAtoms::_asterix,
+                                            false);
+  }
+
+  return mChildrenCollection;
+}
+
+uint32_t
+nsIDocument::ChildElementCount()
+{
+  return Children()->Length();
+}
+
 namespace mozilla {
 
 // Singleton class to manage the list of fullscreen documents which are the
diff --git a/content/base/src/nsINode.cpp b/content/base/src/nsINode.cpp
index d691d2e1b00..c2a94947d8a 100644
--- a/content/base/src/nsINode.cpp
+++ b/content/base/src/nsINode.cpp
@@ -1404,6 +1404,34 @@ nsINode::doInsertChildAt(nsIContent* aKid, uint32_t aIndex,
   return NS_OK;
 }
 
+Element*
+nsINode::GetPreviousElementSibling() const
+{
+  nsIContent* previousSibling = GetPreviousSibling();
+  while (previousSibling) {
+    if (previousSibling->IsElement()) {
+      return previousSibling->AsElement();
+    }
+    previousSibling = previousSibling->GetPreviousSibling();
+  }
+
+  return nullptr;
+}
+
+Element*
+nsINode::GetNextElementSibling() const
+{
+  nsIContent* nextSibling = GetNextSibling();
+  while (nextSibling) {
+    if (nextSibling->IsElement()) {
+      return nextSibling->AsElement();
+    }
+    nextSibling = nextSibling->GetNextSibling();
+  }
+
+  return nullptr;
+}
+
 void
 nsINode::Remove()
 {
@@ -1419,6 +1447,34 @@ nsINode::Remove()
   parent->RemoveChildAt(uint32_t(index), true);
 }
 
+Element*
+nsINode::GetFirstElementChild() const
+{
+  for (nsIContent* child = GetFirstChild();
+       child;
+       child = child->GetNextSibling()) {
+    if (child->IsElement()) {
+      return child->AsElement();
+    }
+  }
+
+  return nullptr;
+}
+
+Element*
+nsINode::GetLastElementChild() const
+{
+  for (nsIContent* child = GetLastChild();
+       child;
+       child = child->GetPreviousSibling()) {
+    if (child->IsElement()) {
+      return child->AsElement();
+    }
+  }
+
+  return nullptr;
+}
+
 void
 nsINode::doRemoveChildAt(uint32_t aIndex, bool aNotify,
                          nsIContent* aKid, nsAttrAndChildArray& aChildArray)
diff --git a/content/base/test/Makefile.in b/content/base/test/Makefile.in
index a148bbd3818..0b5ec03fb52 100644
--- a/content/base/test/Makefile.in
+++ b/content/base/test/Makefile.in
@@ -249,6 +249,7 @@ MOCHITEST_FILES_A = \
 		test_bug820909.html \
 		test_bug704063.html \
 		test_bug894874.html \
+		test_bug895974.html \
 		$(NULL)
 
 MOCHITEST_FILES_B = \
diff --git a/content/base/test/test_bug895974.html b/content/base/test/test_bug895974.html
new file mode 100644
index 00000000000..25499d5a2c1
--- /dev/null
+++ b/content/base/test/test_bug895974.html
@@ -0,0 +1,69 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=895974
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 895974</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 895974 **/
+  SimpleTest.waitForExplicitFinish();
+
+  addLoadEvent(function() {
+  var frag = document.createDocumentFragment();
+  var span = document.createElement("span");
+  var div = document.createElement("div");
+  var text = document.createTextNode("help");
+  frag.appendChild(document.createTextNode("fail"));
+  frag.appendChild(span);
+  frag.appendChild(text);
+  frag.appendChild(div);
+  frag.appendChild(document.createTextNode("fail"));
+
+  is(text.nextElementSibling, div, "nextElementSibling should work on text");
+  is(text.previousElementSibling, span,
+    "previousElementSibling should work on text");
+
+  is(document.firstElementChild, document.documentElement,
+     "firstElementChild should work on document");
+  is(document.lastElementChild, document.documentElement,
+     "lastElementChild should work on document");
+  is(document.children.length, 1, "Document has one element kid");
+  is(document.children[0], document.documentElement,
+     "Document only element child is <html>");
+
+  is(frag.firstElementChild, span,
+     "firstElementChild should work on document fragment");
+  is(frag.lastElementChild, div,
+     "lastElementChild should work on document fragment");
+  is(frag.children.length, 2, "Document fragment has two element kids");
+  is(frag.children[0], span, "Document fragment first element child is span");
+  is(frag.children[1], div, "Document fragment second element child is div");
+
+  is(document.documentElement.firstElementChild, document.head,
+     "firstElementChild should work on element");
+  is(document.documentElement.lastElementChild, document.body,
+     "lastElementChild should work on element");
+  is(document.documentElement.children.length, 2, "<html> has two element kids");
+  is(document.documentElement.children[0], document.head,
+     "<html> first element child is head");
+  is(document.documentElement.children[1], document.body,
+     "<html>  second element child is body");
+  SimpleTest.finish();
+  });
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=895974">Mozilla Bug 895974</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/content/media/test/test_playback_rate_playpause.html b/content/media/test/test_playback_rate_playpause.html
index b868a04b905..7c58daf9094 100644
--- a/content/media/test/test_playback_rate_playpause.html
+++ b/content/media/test/test_playback_rate_playpause.html
@@ -14,6 +14,9 @@ if (navigator.platform.startsWith("Win")) {
   SimpleTest.expectAssertions(0, 1);
 } else if (navigator.platform.startsWith("Mac")) {
   SimpleTest.expectAssertions(0, 2);
+} else if (navigator.platform.startsWith("Linux")) {
+  // Bug 897024
+  SimpleTest.expectAssertions(0, 2);
 }
 
 let manager = new MediaTestManager;
diff --git a/dom/webidl/ChildNode.webidl b/dom/webidl/ChildNode.webidl
index 7032dd4160d..76d448656e1 100644
--- a/dom/webidl/ChildNode.webidl
+++ b/dom/webidl/ChildNode.webidl
@@ -9,9 +9,10 @@
 
 [NoInterfaceObject]
 interface ChildNode {
-// On Element:
-//  readonly attribute Element? previousElementSibling;
-//  readonly attribute Element? nextElementSibling;
+  [Pure]
+  readonly attribute Element? previousElementSibling;
+  [Pure]
+  readonly attribute Element? nextElementSibling;
 
 // Not implemented yet:
 //  void before((Node or DOMString)... nodes);
diff --git a/dom/webidl/Document.webidl b/dom/webidl/Document.webidl
index 91bb605f3c0..81d84c799c7 100644
--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -334,3 +334,4 @@ Document implements XPathEvaluator;
 Document implements GlobalEventHandlers;
 Document implements NodeEventHandlers;
 Document implements TouchEventHandlers;
+Document implements ParentNode;
diff --git a/dom/webidl/DocumentFragment.webidl b/dom/webidl/DocumentFragment.webidl
index 8034ea468d5..45efb296861 100644
--- a/dom/webidl/DocumentFragment.webidl
+++ b/dom/webidl/DocumentFragment.webidl
@@ -29,3 +29,5 @@ partial interface DocumentFragment {
   [Throws]
   NodeList  querySelectorAll(DOMString selectors);
 };
+
+DocumentFragment implements ParentNode;
diff --git a/dom/webidl/Element.webidl b/dom/webidl/Element.webidl
index c7ea13b5032..e837e867afc 100644
--- a/dom/webidl/Element.webidl
+++ b/dom/webidl/Element.webidl
@@ -55,19 +55,6 @@ interface Element : Node {
   HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
   HTMLCollection getElementsByClassName(DOMString classNames);
 
-  [Constant]
-  readonly attribute HTMLCollection children;
-  [Pure]
-  readonly attribute Element? firstElementChild;
-  [Pure]
-  readonly attribute Element? lastElementChild;
-  [Pure]
-  readonly attribute Element? previousElementSibling;
-  [Pure]
-  readonly attribute Element? nextElementSibling;
-  [Pure]
-  readonly attribute unsigned long childElementCount;
-
   /**
    * The ratio of font-size-inflated text font size to computed font
    * size for this element. This will query the element for its primary frame,
@@ -199,3 +186,4 @@ partial interface Element {
 };
 
 Element implements ChildNode;
+Element implements ParentNode;
diff --git a/dom/webidl/ParentNode.webidl b/dom/webidl/ParentNode.webidl
new file mode 100644
index 00000000000..da08b749756
--- /dev/null
+++ b/dom/webidl/ParentNode.webidl
@@ -0,0 +1,24 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * http://dom.spec.whatwg.org/#interface-parentnode
+ */
+
+[NoInterfaceObject]
+interface ParentNode {
+  [Constant]
+  readonly attribute HTMLCollection children;
+  [Pure]
+  readonly attribute Element? firstElementChild;
+  [Pure]
+  readonly attribute Element? lastElementChild;
+  [Pure]
+  readonly attribute unsigned long childElementCount;
+
+  // Not implemented yet
+  // void prepend((Node or DOMString)... nodes);
+  // void append((Node or DOMString)... nodes);
+};
diff --git a/dom/webidl/WebIDL.mk b/dom/webidl/WebIDL.mk
index e98f473856a..f69eec7bc26 100644
--- a/dom/webidl/WebIDL.mk
+++ b/dom/webidl/WebIDL.mk
@@ -209,6 +209,7 @@ webidl_files = \
   PaintRequest.webidl \
   PaintRequestList.webidl \
   PannerNode.webidl \
+  ParentNode.webidl \
   Performance.webidl \
   PerformanceNavigation.webidl \
   PerformanceTiming.webidl \