diff --git a/toolkit/components/places/mozIAsyncFavicons.idl b/toolkit/components/places/mozIAsyncFavicons.idl
index a9b64386c302..bec46bc575d7 100644
--- a/toolkit/components/places/mozIAsyncFavicons.idl
+++ b/toolkit/components/places/mozIAsyncFavicons.idl
@@ -47,7 +47,7 @@ interface nsIFaviconDataCallback;
  * @status EXPERIMENTAL
  */
 
-[scriptable, uuid(0cb4e536-e120-41e6-998f-66123d81ec53)]
+[scriptable, uuid(f3530e8d-0016-4f56-91fe-28958a7ec296)]
 interface mozIAsyncFavicons : nsISupports
 {
   /**
@@ -92,6 +92,73 @@ interface mozIAsyncFavicons : nsISupports
                                  in boolean aForceReload,
                                  [optional] in nsIFaviconDataCallback aCallback);
 
+  /**
+   * Sets the data for a given favicon URI either by replacing existing data in
+   * the database or taking the place of otherwise fetched icon data when
+   * calling setAndFetchFaviconForPage later.
+   *
+   * Favicon data for favicon URIs that are not associated with a page URI via
+   * setAndFetchFaviconForPage will be stored in memory, but may be expired at
+   * any time, so you should make an effort to associate favicon URIs with page
+   * URIs as soon as possible.
+   *
+   * It's better to not use this function for chrome: icon URIs since you can
+   * reference the chrome image yourself. getFaviconLinkForIcon/Page will ignore
+   * any associated data if the favicon URI is "chrome:" and just return the
+   * same chrome URI.
+   *
+   * This function does NOT send out notifications that the data has changed.
+   * Pages using this favicons that are visible in history or bookmarks views
+   * will keep the old icon until they have been refreshed by other means.
+   *
+   * This function tries to optimize the favicon size, if it is bigger
+   * than a defined limit we will try to convert it to a 16x16 png image.
+   * If the conversion fails and favicon is still bigger than our max accepted
+   * size it won't be saved.
+   *
+   * @param aFaviconURI
+   *        URI of the favicon whose data is being set.
+   * @param aData
+   *        Binary contents of the favicon to save
+   * @param aDataLength
+   *        Length of binary data
+   * @param aMimeType
+   *        MIME type of the data to store.  This is important so that we know
+   *        what to report when the favicon is used.  You should always set this
+   *        param unless you are clearing an icon.
+   * @param aExpiration
+   *        Time in microseconds since the epoch when this favicon expires.
+   *        Until this time, we won't try to load it again.
+   * @throws NS_ERROR_FAILURE
+   *         Thrown if the favicon is overbloated and won't be saved to the db.
+   */
+  void replaceFaviconData(in nsIURI aFaviconURI,
+                          [const,array,size_is(aDataLen)] in octet aData,
+                          in unsigned long aDataLen,
+                          in AUTF8String aMimeType,
+                          [optional] in PRTime aExpiration);
+
+  /**
+   * Same as replaceFaviconData but the data is provided by a string
+   * containing a data URL.
+   *
+   * @see replaceFaviconData
+   *
+   * @param aFaviconURI
+   *        URI of the favicon whose data is being set.
+   * @param aDataURL
+   *        string containing a data URL that represents the contents of
+   *        the favicon to save
+   * @param aExpiration
+   *        Time in microseconds since the epoch when this favicon expires.
+   *        Until this time, we won't try to load it again.
+   * @throws NS_ERROR_FAILURE
+   *         Thrown if the favicon is overbloated and won't be saved to the db.
+   */
+  void replaceFaviconDataFromDataURL(in nsIURI aFaviconURI,
+                                     in AString aDataURL,
+                                     [optional] in PRTime aExpiration);
+
   /**
    * Retrieve the URL of the favicon for the given page.
    *
diff --git a/toolkit/components/places/nsIFaviconService.idl b/toolkit/components/places/nsIFaviconService.idl
index f7f826881a13..d0bf066b2334 100644
--- a/toolkit/components/places/nsIFaviconService.idl
+++ b/toolkit/components/places/nsIFaviconService.idl
@@ -151,6 +151,8 @@ interface nsIFaviconService : nsISupports
    *        Until this time, we won't try to load it again.
    * @throws NS_ERROR_FAILURE
    *         Thrown if the favicon is overbloated and won't be saved to the db.
+   *
+   * @deprecated Use mozIAsyncFavicons::replaceFaviconData
    */
   void setFaviconData(in nsIURI aFaviconURI,
                       [const,array,size_is(aDataLen)] in octet aData,
@@ -174,6 +176,8 @@ interface nsIFaviconService : nsISupports
    *        Until this time, we won't try to load it again.
    * @throws NS_ERROR_FAILURE
    *         Thrown if the favicon is overbloated and won't be saved to the db.
+   *
+   * @deprecated Use mozIAsyncFavicons::replaceFaviconDataFromDataURL
    */
   void setFaviconDataFromDataURL(in nsIURI aFaviconURI,
                                  in AString aDataURL,