Inherit plugin content setting to incognito.

This allows flash to be used in incognito as well if the user chooses
to.

Bug: 974721
Change-Id: Ibbc825df65b2a0a6b48944cad2bad82cc733eb43
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1681762
Commit-Queue: Balazs Engedy <engedy@chromium.org>
Reviewed-by: Balazs Engedy <engedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#673343}

components/content_settings/core/browser/content_settings_registry.cc

@@ -176,7 +176,7 @@ void ContentSettingsRegistry::Init() {
                          CONTENT_SETTING_DETECT_IMPORTANT_CONTENT),
            WebsiteSettingsInfo::SINGLE_ORIGIN_WITH_EMBEDDED_EXCEPTIONS_SCOPE,
            WebsiteSettingsRegistry::DESKTOP,
-           ContentSettingsInfo::INHERIT_IF_LESS_PERMISSIVE,
+           ContentSettingsInfo::INHERIT_IN_INCOGNITO,
            ContentSettingsInfo::EPHEMERAL,
            ContentSettingsInfo::EXCEPTIONS_ON_SECURE_AND_INSECURE_ORIGINS);
 

components/content_settings/core/browser/content_settings_registry_unittest.cc

@@ -132,6 +132,7 @@ TEST_F(ContentSettingsRegistryTest, Inheritance) {
   // disable features like popup blocking, download blocking or ad blocking.
   // They do not allow access to user data.
   const ContentSettingsType whitelist[] = {
+      CONTENT_SETTINGS_TYPE_PLUGINS,              //
       CONTENT_SETTINGS_TYPE_POPUPS,               //
       CONTENT_SETTINGS_TYPE_AUTOMATIC_DOWNLOADS,  //
       CONTENT_SETTINGS_TYPE_ADS,                  //