Bug 1593273: Default browser.display.use_system_colors to true on windows, false elsewhere r=emilio,Jamie

Differential Revision: https://phabricator.services.mozilla.com/D125268

accessible/tests/browser/telemetry/browser_HCM_telemetry.js

@@ -96,6 +96,10 @@ 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",
@@ -110,6 +114,11 @@ 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

@@ -1101,7 +1101,11 @@
 
 - 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