Desktop PWAs: re-enable mixed content browser test

The IFrameDynamicMixedContentInPWAReparentWebContentsIntoAppBrowser
EXCPECTs mixed-content behavior that only occurs when the auto-upgrade
flag is disabled. The ...WithAutoupgradesDisabled was accidentally
omitted when moving the test from extensions/ to web_applications/
This caused the test to fail when the ForceWebRequestProxyForTest
or NetworkServiceInProcess feature flags are enabled (as occurs
in  Network Service Linux   bot runs.


Bug: 1052230
Change-Id: Ibad555736525f3f60d9311914b8cd429518530fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2054471Reviewed-by: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Alexey Baskakov <loyso@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741371}

chrome/browser/ui/web_applications/pwa_mixed_content_browsertest.cc

@@ -216,10 +216,9 @@ IN_PROC_BROWSER_TEST_P(PWAMixedContentBrowserTest, IFrameMixedContentInPWA) {
 
 // Tests that iframes can't dynamically load mixed content in a PWA window, when
 // the iframe was created in a regular tab.
-// TODO(crbug.com/1052230): Address Network Service Linux failures, enable test.
 IN_PROC_BROWSER_TEST_P(
-    PWAMixedContentBrowserTest,
-    DISABLED_IFrameDynamicMixedContentInPWAReparentWebContentsIntoAppBrowser) {
+    PWAMixedContentBrowserTestWithAutoupgradesDisabled,
+    IFrameDynamicMixedContentInPWAReparentWebContentsIntoAppBrowser) {
   ASSERT_TRUE(https_server()->Start());
   ASSERT_TRUE(embedded_test_server()->Start());