Bug 1550422 - P1. Add GPU process selector to prefs module. r=spohl,mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D30586

--HG--
extra : moz-landing-system : lando

gfx/thebes/gfxPrefs.h

@@ -195,9 +195,6 @@ class gfxPrefs final {
       CopyPrefValue(&mValue, aOutValue);
     }
     void SetCachedValue(const GfxPrefValue& aOutValue) override {
-      // This is only used in non-XPCOM processes.
-      MOZ_ASSERT(!IsPrefsServiceAvailable());
-
       T newValue;
       CopyPrefValue(&aOutValue, &newValue);
 

modules/libpref/components.conf

@@ -18,7 +18,7 @@ Classes = [
         'type': 'mozilla::Preferences',
         'headers': ['mozilla/Preferences.h'],
         'constructor': 'mozilla::Preferences::GetInstanceForService',
-        'processes': ProcessSelector.ALLOW_IN_RDD_AND_SOCKET_PROCESS,
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_AND_SOCKET_PROCESS,
     },
     {
         'cid': '{064d9cee-1dd2-11b2-83e3-d25ab0193c26}',