Bug 1584931 - P2. Disable flashblock when fission is enabled. r=bytesized

This patch does the following:
  1. Disable flashblock when fission is enabled.
  2. Update flashblock tests to expect "unknown" classification when fission is
     enabled.
  3. Remove skip-if=fission in flashblock mochitests.

Depends on D51098

Differential Revision: https://phabricator.services.mozilla.com/D55091

dom/base/Document.cpp

@@ -15054,9 +15054,14 @@ void Document::TraceProtos(JSTracer* aTrc) {
  * toolkit/components/url-classifier/flash-block-lists.rst
  */
 FlashClassification Document::DocumentFlashClassification() {
+  // Disable flash blocking when fission is enabled(See Bug 1584931).
+  const auto fnIsFlashBlockingEnabled = [] {
+    return StaticPrefs::plugins_flashBlock_enabled() &&
+           !StaticPrefs::fission_autostart();
+  };
+
   // If neither pref is on, skip the null-principal and principal URI checks.
-  if (!StaticPrefs::plugins_http_https_only() &&
-      !StaticPrefs::plugins_flashBlock_enabled()) {
+  if (!StaticPrefs::plugins_http_https_only() && !fnIsFlashBlockingEnabled()) {
     return FlashClassification::Unknown;
   }
 
@@ -15079,7 +15084,7 @@ FlashClassification Document::DocumentFlashClassification() {
 
   // If flash blocking is disabled, it is equivalent to all sites being
   // on neither list.
-  if (!StaticPrefs::plugins_flashBlock_enabled()) {
+  if (!fnIsFlashBlockingEnabled()) {
     return FlashClassification::Unknown;
   }
 

netwerk/url-classifier/UrlClassifierFeatureFlash.cpp

@@ -6,6 +6,7 @@
 
 #include "UrlClassifierFeatureFlash.h"
 #include "mozilla/net/HttpBaseChannel.h"
+#include "mozilla/StaticPrefs_fission.h"
 #include "mozilla/StaticPrefs_plugins.h"
 #include "nsScriptSecurityManager.h"
 #include "nsQueryObject.h"
@@ -96,8 +97,13 @@ void UrlClassifierFeatureFlash::MaybeShutdown() {
 void UrlClassifierFeatureFlash::MaybeCreate(
     nsIChannel* aChannel,
     nsTArray<nsCOMPtr<nsIUrlClassifierFeature>>& aFeatures) {
+  const auto fnIsFlashBlockingEnabled = [] {
+    return StaticPrefs::plugins_flashBlock_enabled() &&
+           !StaticPrefs::fission_autostart();
+  };
+
   // All disabled.
-  if (!StaticPrefs::plugins_flashBlock_enabled()) {
+  if (!fnIsFlashBlockingEnabled()) {
     return;
   }
 

toolkit/components/url-classifier/tests/browser/browser.ini

@@ -6,15 +6,8 @@ support-files =
   simple_blank.swf
 
 [browser_flashblock_on_with_never_activate.js]
-skip-if = fission
 [browser_flashblock_off_with_never_activate.js]
-skip-if = fission
 [browser_flashblock_on_with_ask_to_activate.js]
-skip-if = fission
 [browser_flashblock_off_with_ask_to_activate.js]
-skip-if = fission
 [browser_flashblock_on_with_always_activate.js]
-skip-if = fission
 [browser_flashblock_off_with_always_activate.js]
-
-skip-if = fission

toolkit/components/url-classifier/tests/browser/classifierTester.js

@@ -10,6 +10,7 @@ var classifierTester = {
   FLASHBLOCK_ENABLE_PREF: "plugins.flashBlock.enabled",
   FLASH_PLUGIN_USER_SETTING_PREF: "plugin.state.flash",
   URLCLASSIFIER_DISALLOW_COMPLETIONS_PREF: "urlclassifier.disallow_completions",
+  FISSION_PREF: "fission.autostart",
   NEVER_ACTIVATE_PREF_VALUE: 0,
   ASK_TO_ACTIVATE_PREF_VALUE: 1,
   ALWAYS_ACTIVATE_PREF_VALUE: 2,
@@ -382,6 +383,12 @@ var classifierTester = {
   },
 
   checkPluginInfo(pluginInfo, expectedClassification, flashSetting) {
+    // Flashblocking is disabled when fission is enabled, so all the classifications
+    // should be "unknown"
+    if (Services.prefs.getBoolPref(classifierTester.FISSION_PREF)) {
+      expectedClassification = "unknown";
+    }
+
     // We've stopped allowing flash to be always activated, so check
     // existing tests that attempt to do so get treated as using ask-to-activate.
     if (flashSetting == classifierTester.ALWAYS_ACTIVATE_PREF_VALUE) {