Bug 1845666 - Lock the media.utility-* prefs r=alwu

Differential Revision: https://phabricator.services.mozilla.com/D184734

dom/media/MediaDecoder.cpp

@@ -126,6 +126,33 @@ void MediaDecoder::InitStatics() {
   MOZ_ASSERT(NS_IsMainThread());
   // Eagerly init gMediaDecoderLog to work around bug 1415441.
   MOZ_LOG(gMediaDecoderLog, LogLevel::Info, ("MediaDecoder::InitStatics"));
+
+#if defined(NIGHTLY_BUILD)
+  // Allow people to force a bit but try to warn them about filing bugs if audio
+  // decoding does not work on utility
+  static const bool allowLockPrefs =
+      PR_GetEnv("MOZ_DONT_LOCK_UTILITY_PLZ_FILE_A_BUG") == nullptr;
+  if (XRE_IsParentProcess() && allowLockPrefs) {
+    // Lock Utility process preferences so that people cannot opt-out of
+    // Utility process
+    Preferences::Lock("media.utility-process.enabled");
+#  if defined(MOZ_FFMPEG)
+    Preferences::Lock("media.utility-ffmpeg.enabled");
+#  endif  // defined(MOZ_FFMPEG)
+#  if defined(MOZ_FFVPX)
+    Preferences::Lock("media.utility-ffvpx.enabled");
+#  endif  // defined(MOZ_FFVPX)
+#  if defined(MOZ_WMF)
+    Preferences::Lock("media.utility-wmf.enabled");
+#  endif  // defined(MOZ_WMF)
+#  if defined(MOZ_APPLEMEDIA)
+    Preferences::Lock("media.utility-applemedia.enabled");
+#  endif  // defined(MOZ_APPLEMEDIA)
+    Preferences::Lock("media.utility-vorbis.enabled");
+    Preferences::Lock("media.utility-wav.enabled");
+    Preferences::Lock("media.utility-opus.enabled");
+  }
+#endif  // defined(NIGHTLY_BUILD)
 }
 
 NS_IMPL_ISUPPORTS(MediaMemoryTracker, nsIMemoryReporter)

ipc/glue/test/browser/browser.ini

@@ -1,5 +1,9 @@
 [DEFAULT]
 support-files = head.js
+# Set this since we want to continue monitoring the disabling of pref since we
+# still allow it a little bit.
+environment =
+  MOZ_DONT_LOCK_UTILITY_PLZ_FILE_A_BUG=1
 
 [browser_audio_telemetry_content.js]
 skip-if =

ipc/glue/test/browser/browser_audio_fallback.ini

@@ -4,6 +4,10 @@ support-files =
   head-multiple.js
 prefs =
   media.allow-audio-non-utility=true
+# Set this since we want to continue monitoring the disabling of pref since we
+# still allow it a little bit.
+environment =
+  MOZ_DONT_LOCK_UTILITY_PLZ_FILE_A_BUG=1
 
 [browser_utility_multipleAudio_fallback.js]
 support-files =

ipc/glue/test/browser/browser_audio_locked.ini

@@ -0,0 +1,3 @@
+[DEFAULT]
+
+[browser_utility_audio_locked.js]

ipc/glue/test/browser/browser_utility_audio_locked.js

@@ -0,0 +1,24 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from head-multiple.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/ipc/glue/test/browser/head-multiple.js",
+  this
+);
+
+add_setup(async function setup() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["media.utility-process.enabled", false]],
+  });
+});
+
+add_task(async function testAudioDecodingInUtility() {
+  // TODO: When getting rid of audio decoding on non utility at all, this
+  // should be removed
+  const verifyForUtility = !!isNightly();
+  await runTest({ expectUtility: verifyForUtility });
+});

ipc/glue/test/browser/moz.build

@@ -8,6 +8,7 @@ BROWSER_CHROME_MANIFESTS += [
     "browser.ini",
     "browser_audio_fallback.ini",
     "browser_audio_fallback_content.ini",
+    "browser_audio_locked.ini",
     "browser_audio_shutdown.ini",
     "browser_child_hang.ini",
 ]

toolkit/modules/tests/browser/browser_Troubleshoot.js

@@ -526,6 +526,38 @@ const SNAPSHOT_SCHEMA = {
           required: false,
           type: "boolean",
         },
+        "media.utility-process.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-ffmpeg.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-ffvpx.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-wmf.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-applemedia.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-vorbis.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-wav.enabled": {
+          required: false,
+          type: "boolean",
+        },
+        "media.utility-opus.enabled": {
+          required: false,
+          type: "boolean",
+        },
       },
     },
     places: {