Bug 1441857 - Added comment explaining custom properties are directly from CSSOM in order to get predefined style which is why they are not referenced by CSS. r=jaws

--HG--
extra : rebase_source : be31080cf5fbcb92578d02a07e0102df4d712f3a

browser/base/content/test/static/browser_parsable_css.js

@@ -102,27 +102,6 @@ let propNameWhitelist = [
   // Bug 1441855
   {propName: "--chrome-nav-buttons-hover-background",
    isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--muteButton-width",
-   isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--closedCaptionButton-width",
-   isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--fullscreenButton-width",
-   isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--durationSpan-width",
-   isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--durationSpan-width-long",
-   isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--positionDurationBox-width",
-   isFromDevTools: false},
-  // Bug 1441857
-  {propName: "--positionDurationBox-width-long",
-   isFromDevTools: false},
   // Bug 1441929
   {propName: "--theme-search-overlays-semitransparent",
    isFromDevTools: true},
@@ -132,7 +111,23 @@ let propNameWhitelist = [
   // Bug 1442300
   {propName: "--in-content-category-background",
    isFromDevTools: false},
-
+  // These custom properties are retrieved directly from CSSOM
+  // in videocontrols.xml to get pre-defined style instead of computed
+  // dimensions, which is why they are not referenced by CSS.
+  {propName: "--muteButton-width",
+   isFromDevTools: false},
+  {propName: "--closedCaptionButton-width",
+   isFromDevTools: false},
+  {propName: "--fullscreenButton-width",
+   isFromDevTools: false},
+  {propName: "--durationSpan-width",
+   isFromDevTools: false},
+  {propName: "--durationSpan-width-long",
+   isFromDevTools: false},
+  {propName: "--positionDurationBox-width",
+   isFromDevTools: false},
+  {propName: "--positionDurationBox-width-long",
+   isFromDevTools: false},
   // Used on Linux
   {propName: "--in-content-box-background-odd",
    platforms: ["win", "macosx"],

toolkit/themes/shared/media/videocontrols.css

@@ -14,6 +14,7 @@ audio > xul|videocontrols {
   overflow: hidden;
 }
 
+/* Some CSS custom properties defined here are referenced by videocontrols.xml in JavaScript */
 .controlBar {
   --clickToPlay-width: 48px;
   --clickToPlay-height: var(--clickToPlay-width);