--- a/dom/base/nsDeprecatedOperationList.h
+++ b/dom/base/nsDeprecatedOperationList.h
@@ -41,9 +41,8 @@ DEPRECATED_OPERATION(XMLBaseAttribute)
 DEPRECATED_OPERATION(WindowContentUntrusted)
 DEPRECATED_OPERATION(RegisterProtocolHandlerInsecure)
 DEPRECATED_OPERATION(MixedDisplayObjectSubrequest)
 DEPRECATED_OPERATION(MotionEvent)
 DEPRECATED_OPERATION(OrientationEvent)
 DEPRECATED_OPERATION(ProximityEvent)
 DEPRECATED_OPERATION(AmbientLightEvent)
 DEPRECATED_OPERATION(IDBOpenDBOptions_StorageType)
-DEPRECATED_OPERATION(GetPropertyCSSValue)

--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -351,10 +351,8 @@ ReadableStreamReadingFailed=Failed to read data from the ReadableStream: “%S”.
 RegisterProtocolHandlerInsecureWarning=Use of the registerProtocolHandler for insecure connections will be removed in version 62.
 MixedDisplayObjectSubrequestWarning=Loading insecure content within a plugin embedded in a secure connection is going to be removed.
 MotionEventWarning=Use of the motion sensor is deprecated.
 OrientationEventWarning=Use of the orientation sensor is deprecated.
 ProximityEventWarning=Use of the proximity sensor is deprecated.
 AmbientLightEventWarning=Use of the ambient light sensor is deprecated.
 # LOCALIZATION NOTE: Do not translate "storage", "indexedDB.open" and "navigator.storage.persist()".
 IDBOpenDBOptions_StorageTypeWarning=The ‘storage’ attribute in options passed to indexedDB.open is deprecated and will soon be removed. To get persistent storage, please use navigator.storage.persist() instead.
-# LOCALIZATION NOTE: Do not translate "getPropertyCSSValue" and "getPropertyValue".
-GetPropertyCSSValueWarning=Use of getPropertyCSSValue is deprecated, use getPropertyValue instead.

--- a/dom/webidl/CSSStyleDeclaration.webidl
+++ b/dom/webidl/CSSStyleDeclaration.webidl
@@ -14,19 +14,16 @@ interface CSSStyleDeclaration {
   readonly attribute unsigned long length;
   getter DOMString item(unsigned long index);
 
   [Throws, ChromeOnly]
   sequence<DOMString> getCSSImageURLs(DOMString property);
 
   [Throws]
   DOMString getPropertyValue(DOMString property);
-  // Mozilla extension, sort of
-  [Throws, Pref="layout.css.getPropertyCSSValue.enabled"]
-  CSSValue? getPropertyCSSValue(DOMString property);
   DOMString getPropertyPriority(DOMString property);
   [CEReactions, NeedsSubjectPrincipal=NonSystem, Throws]
   void setProperty(DOMString property, [TreatNullAs=EmptyString] DOMString value, [TreatNullAs=EmptyString] optional DOMString priority = "");
   [CEReactions, Throws]
   DOMString removeProperty(DOMString property);
 
   readonly attribute CSSRule? parentRule;
 };

--- a/editor/libeditor/CSSEditUtils.cpp
+++ b/editor/libeditor/CSSEditUtils.cpp
@@ -636,20 +636,16 @@ CSSEditUtils::GetDefaultLengthUnit(nsASt
   nsresult rv =
     Preferences::GetString("editor.css.default_length_unit", aLengthUnit);
   // XXX Why don't you validate the pref value?
   if (NS_FAILED(rv)) {
     aLengthUnit.AssignLiteral("px");
   }
 }
 
-// Unfortunately, CSSStyleDeclaration::GetPropertyCSSValue is not yet
-// implemented... We need then a way to determine the number part and the unit
-// from aString, aString being the result of a GetPropertyValue query...
-
 // static
 void
 CSSEditUtils::ParseLength(const nsAString& aString,
                           float* aValue,
                           nsAtom** aUnit)
 {
   if (aString.IsEmpty()) {
     *aValue = 0;

--- a/editor/libeditor/CSSEditUtils.h
+++ b/editor/libeditor/CSSEditUtils.h
@@ -268,19 +268,17 @@ public:
    */
   nsresult RemoveCSSEquivalentToHTMLStyle(dom::Element* aElement,
                                           nsAtom* aHTMLProperty,
                                           nsAtom* aAttribute,
                                           const nsAString* aValue,
                                           bool aSuppressTransaction);
 
   /**
-   * Parses a "xxxx.xxxxxuuu" string where x is a digit and u an alpha char
-   * we need such a parser because
-   * nsIDOMCSSStyleDeclaration::GetPropertyCSSValue() is not implemented.
+   * Parses a "xxxx.xxxxxuuu" string where x is a digit and u an alpha char.
    *
    * @param aString        [IN] Input string to parse.
    * @param aValue         [OUT] Numeric part.
    * @param aUnit          [OUT] Unit part.
    */
   static void ParseLength(const nsAString& aString, float* aValue,
                           nsAtom** aUnit);
 

--- a/editor/libeditor/ChangeStyleTransaction.cpp
+++ b/editor/libeditor/ChangeStyleTransaction.cpp
@@ -178,20 +178,16 @@ ChangeStyleTransaction::DoTransaction()
 
   // Does this property accept more than one value? (bug 62682)
   bool multiple = AcceptsMoreThanOneValue(*mProperty);
 
   if (mRemoveProperty) {
     nsAutoString returnString;
     if (multiple) {
       // Let's remove only the value we have to remove and not the others
-
-      // The two lines below are a workaround because
-      // nsDOMCSSDeclaration::GetPropertyCSSValue is not yet implemented (bug
-      // 62682)
       RemoveValueFromListOfValues(values, NS_LITERAL_STRING("none"));
       RemoveValueFromListOfValues(values, mValue);
       if (values.IsEmpty()) {
         rv = cssDecl->RemoveProperty(propertyNameString, returnString);
         NS_ENSURE_SUCCESS(rv, rv);
       } else {
         nsAutoString priority;
         cssDecl->GetPropertyPriority(propertyNameString, priority);
@@ -202,20 +198,16 @@ ChangeStyleTransaction::DoTransaction()
       rv = cssDecl->RemoveProperty(propertyNameString, returnString);
       NS_ENSURE_SUCCESS(rv, rv);
     }
   } else {
     nsAutoString priority;
     cssDecl->GetPropertyPriority(propertyNameString, priority);
     if (multiple) {
       // Let's add the value we have to add to the others
-
-      // The line below is a workaround because
-      // nsDOMCSSDeclaration::GetPropertyCSSValue is not yet implemented (bug
-      // 62682)
       AddValueToMultivalueProperty(values, mValue);
     } else {
       values.Assign(mValue);
     }
     rv = cssDecl->SetProperty(propertyNameString, values, priority);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 

--- a/layout/style/ServoFontFaceRule.cpp
+++ b/layout/style/ServoFontFaceRule.cpp
@@ -61,25 +61,16 @@ NS_IMETHODIMP
 ServoFontFaceRuleDecl::GetPropertyValue(const nsAString& aPropName,
                                         nsAString& aResult)
 {
   aResult.Truncate();
   GetPropertyValue(nsCSSProps::LookupFontDesc(aPropName), aResult);
   return NS_OK;
 }
 
-already_AddRefed<dom::CSSValue>
-ServoFontFaceRuleDecl::GetPropertyCSSValue(const nsAString& aPropName,
-                                           ErrorResult& aRv)
-{
-  // ??? nsDOMCSSDeclaration returns null/NS_OK, but that seems wrong.
-  aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
-  return nullptr;
-}
-
 NS_IMETHODIMP
 ServoFontFaceRuleDecl::RemoveProperty(const nsAString& aPropName,
                                       nsAString& aResult)
 {
   nsCSSFontDesc descID = nsCSSProps::LookupFontDesc(aPropName);
   NS_ASSERTION(descID >= eCSSFontDesc_UNKNOWN &&
                descID < eCSSFontDesc_COUNT,
                "LookupFontDesc returned value out of range");

--- a/layout/style/ServoFontFaceRule.h
+++ b/layout/style/ServoFontFaceRule.h
@@ -16,20 +16,16 @@ namespace mozilla {
 // A ServoFontFaceRuleDecl is always embeded in a ServoFontFaceRule.
 class ServoFontFaceRule;
 class ServoFontFaceRuleDecl final : public nsICSSDeclaration
 {
 public:
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_NSIDOMCSSSTYLEDECLARATION_HELPER
 
-  already_AddRefed<dom::CSSValue>
-  GetPropertyCSSValue(const nsAString& aProp, ErrorResult& aRv) final;
-  using nsICSSDeclaration::GetPropertyCSSValue;
-
   nsINode* GetParentObject() final;
   void IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aPropName) final;
 
   void GetPropertyValue(nsCSSFontDesc aFontDescID, nsAString& aResult) const;
 
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) final;
 
 protected:

--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -983,26 +983,16 @@ nsComputedDOMStyle::ClearCurrentStyleSou
   }
 
   mOuterFrame = nullptr;
   mInnerFrame = nullptr;
   mPresShell = nullptr;
 }
 
 already_AddRefed<CSSValue>
-nsComputedDOMStyle::GetPropertyCSSValue(const nsAString& aPropertyName,
-                                        ErrorResult& aRv)
-{
-  if (nsCOMPtr<nsIDocument> document = do_QueryReferent(mDocumentWeak)) {
-    document->WarnOnceAbout(nsIDocument::eGetPropertyCSSValue);
-  }
-  return GetPropertyCSSValueWithoutWarning(aPropertyName, aRv);
-}
-
-already_AddRefed<CSSValue>
 nsComputedDOMStyle::GetPropertyCSSValueWithoutWarning(
   const nsAString& aPropertyName,
   ErrorResult& aRv)
 {
   nsCSSPropertyID prop =
     nsCSSProps::LookupProperty(aPropertyName, CSSEnabledState::eForAllContent);
 
   bool needsLayoutFlush;

--- a/layout/style/nsComputedDOMStyle.h
+++ b/layout/style/nsComputedDOMStyle.h
@@ -69,21 +69,16 @@ public:
 
   NS_DECL_NSIDOMCSSSTYLEDECLARATION_HELPER
   nsresult GetPropertyValue(const nsCSSPropertyID aPropID,
                             nsAString& aValue) override;
   nsresult SetPropertyValue(const nsCSSPropertyID aPropID,
                             const nsAString& aValue,
                             nsIPrincipal* aSubjectPrincipal) override;
 
-  // Do NOT use this, it is deprecated, see bug 474655.
-  already_AddRefed<CSSValue>
-  GetPropertyCSSValue(const nsAString& aProp, mozilla::ErrorResult& aRv) final;
-  using nsICSSDeclaration::GetPropertyCSSValue;
-
   void IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aPropName) final;
 
   enum StyleType {
     eDefaultOnly, // Only includes UA and user sheets
     eAll // Includes all stylesheets
   };
 
   nsComputedDOMStyle(mozilla::dom::Element* aElement,

--- a/layout/style/nsDOMCSSDeclaration.cpp
+++ b/layout/style/nsDOMCSSDeclaration.cpp
@@ -139,24 +139,16 @@ nsDOMCSSDeclaration::Length()
 
   if (decl) {
     return decl->Count();
   }
 
   return 0;
 }
 
-already_AddRefed<dom::CSSValue>
-nsDOMCSSDeclaration::GetPropertyCSSValue(const nsAString& aPropertyName, ErrorResult& aRv)
-{
-  // We don't support CSSValue yet so we'll just return null...
-
-  return nullptr;
-}
-
 void
 nsDOMCSSDeclaration::IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aPropName)
 {
   DeclarationBlock* decl = GetCSSDeclaration(eOperation_Read);
   aFound = decl && decl->GetNthProperty(aIndex, aPropName);
 }
 
 NS_IMETHODIMP

--- a/layout/style/nsDOMCSSDeclaration.h
+++ b/layout/style/nsDOMCSSDeclaration.h
@@ -62,20 +62,16 @@ public:
   // Require subclasses to implement |GetParentRule|.
   //NS_DECL_NSIDOMCSSSTYLEDECLARATION
   void GetCssText(nsAString & aCssText) override;
   void SetCssText(const nsAString & aCssText,
                   nsIPrincipal* aSubjectPrincipal,
                   mozilla::ErrorResult& aRv) override;
   NS_IMETHOD GetPropertyValue(const nsAString & propertyName,
                               nsAString & _retval) override;
-  virtual already_AddRefed<mozilla::dom::CSSValue>
-    GetPropertyCSSValue(const nsAString & propertyName,
-                        mozilla::ErrorResult& aRv) override;
-  using nsICSSDeclaration::GetPropertyCSSValue;
   NS_IMETHOD RemoveProperty(const nsAString & propertyName,
                             nsAString & _retval) override;
   void GetPropertyPriority(const nsAString & propertyName,
                            nsAString & aPriority) override;
   NS_IMETHOD SetProperty(const nsAString& propertyName,
                          const nsAString& value,
                          const nsAString& priority,
                          nsIPrincipal* aSubjectPrincipal) override;

--- a/layout/style/nsICSSDeclaration.h
+++ b/layout/style/nsICSSDeclaration.h
@@ -48,19 +48,16 @@ class nsICSSDeclaration : public nsISupp
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICSSDECLARATION_IID)
 
   virtual nsINode *GetParentObject() = 0;
   mozilla::dom::DocGroup* GetDocGroup();
 
   NS_IMETHOD GetPropertyValue(const nsAString& aPropName,
                               nsAString& aValue) = 0;
-  virtual already_AddRefed<mozilla::dom::CSSValue>
-    GetPropertyCSSValue(const nsAString& aPropertyName,
-                        mozilla::ErrorResult& aRv) = 0;
   NS_IMETHOD RemoveProperty(const nsAString& aPropertyName,
                             nsAString& aReturn) = 0;
   NS_IMETHOD SetProperty(const nsAString& aPropertyName,
                          const nsAString& aValue,
                          const nsAString& aPriority,
                          nsIPrincipal* aSubjectPrincipal = nullptr) = 0;
   void Item(uint32_t aIndex, nsAString& aReturn)
   {

--- a/layout/style/test/mochitest.ini
+++ b/layout/style/test/mochitest.ini
@@ -1,12 +1,11 @@
 [DEFAULT]
 prefs =
   dom.animations-api.core.enabled=true
-  layout.css.getPropertyCSSValue.enabled=true
 support-files =
   animation_utils.js
   ccd-quirks.html
   ccd.sjs
   ccd-standards.html
   chrome/bug418986-2.js
   chrome/match.png
   chrome/mismatch.png

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2817,22 +2817,16 @@ pref("layout.word_select.stop_at_undersc
 // 3 = caret moves and blinks as when there is no selection; word delete
 //     deletes the selection
 // Windows default is 1 for word delete behavior, the rest as for 2.
 pref("layout.selection.caret_style", 0);
 
 // pref to report CSS errors to the error console
 pref("layout.css.report_errors", true);
 
-#ifdef NIGHTLY_BUILD
-pref("layout.css.getPropertyCSSValue.enabled", false);
-#else
-pref("layout.css.getPropertyCSSValue.enabled", true);
-#endif
-
 // Override DPI. A value of -1 means use the maximum of 96 and the system DPI.
 // A value of 0 means use the system DPI. A positive value is used as the DPI.
 // This sets the physical size of a device pixel and thus controls the
 // interpretation of physical units such as "pt".
 pref("layout.css.dpi", -1);
 
 // Set the number of device pixels per CSS pixel. A value <= 0 means choose
 // automatically based on user settings for the platform (e.g., "UI scale factor"