Desktop PWAs: Disable minimal-ui on Mac

The Mac icons for minimal-ui are not implemented yet.

Desktop minimal-ui will initially ship on Chrome OS, Windows and Linux.

Bug: 1028393
Change-Id: If3fc14a7829ce3a9fe866eceb92b09ce6b2b8a14
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1952043
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Auto-Submit: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Alan Cutter <alancutter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721779}

chrome/common/chrome_features.cc

@@ -247,8 +247,14 @@ const base::Feature kDesktopCaptureTabSharingInfobar{
     "DesktopCaptureTabSharingInfobar", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Enables or disables new Desktop PWA support for minimal-ui display mode.
-const base::Feature kDesktopMinimalUI{"DesktopMinimalUI",
-                                      base::FEATURE_ENABLED_BY_DEFAULT};
+const base::Feature kDesktopMinimalUI {
+  "DesktopMinimalUI",
+#if defined(OS_MACOSX)
+      base::FEATURE_DISABLED_BY_DEFAULT
+#else
+      base::FEATURE_ENABLED_BY_DEFAULT
+#endif
+};
 
 // Enables or disables new Desktop PWAs implementation that does not use
 // extensions.