Backed out changeset f2f9361b8e5e (bug 1593273) for causing failures at test_default_background.xhtml.

accessible/tests/browser/telemetry/browser_HCM_telemetry.js

@@ -96,10 +96,6 @@ add_task(async function testInit() {
   const dialogWin = await openColorsDialog();
   const menulistHCM = dialogWin.document.getElementById("useDocumentColors");
   if (AppConstants.platform == "win") {
-    ok(
-      Services.prefs.getBoolPref("browser.display.use_system_colors"),
-      "Use system colors is on by default on windows"
-    );
     is(
       menulistHCM.value,
       "0",
@@ -114,11 +110,6 @@ add_task(async function testInit() {
       false
     );
   } else {
-    ok(
-      !Services.prefs.getBoolPref("browser.display.use_system_colors"),
-      "Use system colors is off by default on non-windows platforms"
-    );
-
     is(
       menulistHCM.value,
       "1",

modules/libpref/init/StaticPrefList.yaml

@@ -1101,11 +1101,7 @@
 
 - name: browser.display.use_system_colors
   type: bool
-#ifdef XP_WIN
-  value: true
-#else
   value: false
-#endif
   mirror: always
 
 - name: browser.dom.window.dump.enabled