--- a/layout/generic/nsCanvasFrame.cpp
+++ b/layout/generic/nsCanvasFrame.cpp
@@ -71,46 +71,37 @@ nsCanvasFrame::CreateAnonymousContent(ns
                                                    nsIDOMNode::ELEMENT_NODE);
     NS_ENSURE_TRUE(nodeInfo, NS_ERROR_OUT_OF_MEMORY);
 
     rv = NS_NewHTMLElement(getter_AddRefs(mTouchCaretElement), nodeInfo.forget(),
                            mozilla::dom::NOT_FROM_PARSER);
     NS_ENSURE_SUCCESS(rv, rv);
     aElements.AppendElement(mTouchCaretElement);
 
-    // Add a _moz_anonclass attribute as touch caret selector.
-    mTouchCaretElement->SetAttribute(NS_LITERAL_STRING("_moz_anonclass"),
-                                     NS_LITERAL_STRING("mozTouchCaret"), er);
-    NS_ENSURE_SUCCESS(er.ErrorCode(), er.ErrorCode());
-
     // Set touch caret to visibility: hidden by default.
     nsAutoString classValue;
     classValue.AppendLiteral("moz-touchcaret hidden");
     rv = mTouchCaretElement->SetAttr(kNameSpaceID_None, nsGkAtoms::_class,
                                      classValue, true);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   if (PresShell::SelectionCaretPrefEnabled()) {
     // Selection caret
     mSelectionCaretsStartElement = doc->CreateHTMLElement(nsGkAtoms::div);
     aElements.AppendElement(mSelectionCaretsStartElement);
 
     mSelectionCaretsEndElement = doc->CreateHTMLElement(nsGkAtoms::div);
     aElements.AppendElement(mSelectionCaretsEndElement);
 
-    mSelectionCaretsStartElement->SetAttribute(NS_LITERAL_STRING("_moz_anonclass"),
-                                               NS_LITERAL_STRING("mozTouchCaret"), er);
     rv = mSelectionCaretsStartElement->SetAttr(kNameSpaceID_None, nsGkAtoms::_class,
                                                NS_LITERAL_STRING("moz-selectioncaret-left hidden"),
                                                true);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    mSelectionCaretsEndElement->SetAttribute(NS_LITERAL_STRING("_moz_anonclass"),
-                                             NS_LITERAL_STRING("mozTouchCaret"), er);
     rv = mSelectionCaretsEndElement->SetAttr(kNameSpaceID_None, nsGkAtoms::_class,
                                              NS_LITERAL_STRING("moz-selectioncaret-right hidden"),
                                              true);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   return NS_OK;
 }

--- a/layout/style/ua.css
+++ b/layout/style/ua.css
@@ -304,89 +304,89 @@ parsererror|sourcetext {
   font-family: -moz-fixed;
   margin-top: 2em;
   margin-bottom: 1em;
   color: red;
   font-weight: bold;
   font-size: 12pt;
 }
 
-div[\_moz_anonclass="mozTouchCaret"].moz-touchcaret,
-div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left,
-div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right {
+div:-moz-native-anonymous.moz-touchcaret,
+div:-moz-native-anonymous.moz-selectioncaret-left,
+div:-moz-native-anonymous.moz-selectioncaret-right {
   background-image: url("resource://gre/res/text_caret.png");
   position: absolute;
   width: 29px;
   height: 31px;
   margin-left: -15px;
   background-position: center center;
   background-size: 100% 100%;
   z-index: 2147483647;
 }
 
-div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left.tilt {
+div:-moz-native-anonymous.moz-selectioncaret-left.tilt {
   background-image: url("resource://gre/res/text_caret_tilt_left.png");
   margin-left: -29px;
   width: 29px;
 }
 
-div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right.tilt {
+div:-moz-native-anonymous.moz-selectioncaret-right.tilt {
   background-image: url("resource://gre/res/text_caret_tilt_right.png");
   margin-left: 0px;
   width: 29px;
 }
 
 @media (min-resolution: 1.5dppx) {
-  div[\_moz_anonclass="mozTouchCaret"].moz-touchcaret,
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left,
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right {
+  div:-moz-native-anonymous.moz-touchcaret,
+  div:-moz-native-anonymous.moz-selectioncaret-left,
+  div:-moz-native-anonymous.moz-selectioncaret-right {
     background-image: url("resource://gre/res/text_caret@1.5x.png");
   }
 
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left.tilt {
+  div:-moz-native-anonymous.moz-selectioncaret-left.tilt {
     background-image: url("resource://gre/res/text_caret_tilt_left@1.5x.png");
   }
 
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right.tilt {
+  div:-moz-native-anonymous.moz-selectioncaret-right.tilt {
     background-image: url("resource://gre/res/text_caret_tilt_right@1.5x.png");
   }
 }
 
 @media (min-resolution: 2dppx) {
-  div[\_moz_anonclass="mozTouchCaret"].moz-touchcaret,
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left,
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right {
+  div:-moz-native-anonymous.moz-touchcaret,
+  div:-moz-native-anonymous.moz-selectioncaret-left,
+  div:-moz-native-anonymous.moz-selectioncaret-right {
     background-image: url("resource://gre/res/text_caret@2x.png");
   }
 
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left.tilt {
+  div:-moz-native-anonymous.moz-selectioncaret-left.tilt {
     background-image: url("resource://gre/res/text_caret_tilt_left@2x.png");
   }
 
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right.tilt {
+  div:-moz-native-anonymous.moz-selectioncaret-right.tilt {
     background-image: url("resource://gre/res/text_caret_tilt_right@2x.png");
   }
 }
 
 @media (min-resolution: 2.25dppx) {
-  div[\_moz_anonclass="mozTouchCaret"].moz-touchcaret,
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left,
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right {
+  div:-moz-native-anonymous.moz-touchcaret,
+  div:-moz-native-anonymous.moz-selectioncaret-left,
+  div:-moz-native-anonymous.moz-selectioncaret-right {
     background-image: url("resource://gre/res/text_caret@2.25x.png");
   }
 
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left.tilt {
+  div:-moz-native-anonymous.moz-selectioncaret-left.tilt {
     background-image: url("resource://gre/res/text_caret_tilt_left@2.25x.png");
   }
 
-  div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right.tilt {
+  div:-moz-native-anonymous.moz-selectioncaret-right.tilt {
     background-image: url("resource://gre/res/text_caret_tilt_right@2.25x.png");
   }
 }
 
-div[\_moz_anonclass="mozTouchCaret"].moz-touchcaret.hidden,
-div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-left.hidden,
-div[\_moz_anonclass="mozTouchCaret"].moz-selectioncaret-right.hidden {
+div:-moz-native-anonymous.moz-touchcaret.hidden,
+div:-moz-native-anonymous.moz-selectioncaret-left.hidden,
+div:-moz-native-anonymous.moz-selectioncaret-right.hidden {
   width: 0px;
   height: 0px;
   margin: 0px;
   visibility: hidden;
 }