Bug 1527960 - Rename 'browser.fission.oopif.attribute' to 'fission.oopif.attribute'. r=nika

Differential Revision: https://phabricator.services.mozilla.com/D21716

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

dom/base/nsFrameLoader.cpp

@@ -1797,7 +1797,7 @@ bool nsFrameLoader::ShouldUseRemoteProcess() {
 
   // Check if the force fission test attribute is enabled.
   if (XRE_IsContentProcess() &&
-      Preferences::GetBool("browser.fission.oopif.attribute", false) &&
+      Preferences::GetBool("fission.oopif.attribute", false) &&
       mOwnerContent->HasAttr(kNameSpaceID_None, nsGkAtoms::fission)) {
     return true;
   }

dom/ipc/tests/test_force_oop_iframe.html

@@ -13,7 +13,7 @@
 /* eslint-env mozilla/frame-script */
 
 add_task(async function() {
-  await SpecialPowers.pushPrefEnv({"set": [["browser.fission.oopif.attribute", true]]});
+  await SpecialPowers.pushPrefEnv({"set": [["fission.oopif.attribute", true]]});
 
   // This iframe should be loaded out of process. Unfortunately as of the time
   // of this test's creation, many different events which we could use to detect