Bug 1351425 - Only temp. qualify for e10s when enabled at <100%. r=Felipe

This tweaks the temporary qualification step (currently used only for DevTools)
so that it does not apply on channels that are 100% enabled anyway.  This does
not change how many users receive e10s on, it only tweaks who falls into which
cohort, since there's no reason to push all DevTools users to a special cohort
if everyone would have received e10s on anyway.

MozReview-Commit-ID: 5Yn6M50Ny1w

browser/extensions/e10srollout/bootstrap.js

@@ -84,7 +84,8 @@ function defineCohort() {
   let userOptedOut = optedOut();
   let userOptedIn = optedIn();
   let disqualified = (Services.appinfo.multiprocessBlockPolicy != 0);
-  let testGroup = (getUserSample() < TEST_THRESHOLD[updateChannel]);
+  let testThreshold = TEST_THRESHOLD[updateChannel];
+  let testGroup = (getUserSample() < testThreshold);
   let hasNonExemptAddon = Preferences.get(PREF_E10S_HAS_NONEXEMPT_ADDON, false);
   let temporaryDisqualification = getTemporaryDisqualification();
   let temporaryQualification = getTemporaryQualification();
@@ -111,7 +112,11 @@ function defineCohort() {
     // here will be accumulated as "2 - Disabled", which is fine too.
     setCohort(`temp-disqualified-${temporaryDisqualification}`);
     Preferences.reset(PREF_TOGGLE_E10S);
-  } else if (!disqualified && temporaryQualification != "") {
+  } else if (!disqualified && testThreshold < 1.0 &&
+             temporaryQualification != "") {
+    // Users who are qualified for e10s and on channels where some population
+    // would not receive e10s can be pushed into e10s anyway via a temporary
+    // qualification which overrides the user sample value when non-empty.
     setCohort(`temp-qualified-${temporaryQualification}`);
     Preferences.set(PREF_TOGGLE_E10S, true);
   } else if (testGroup) {

browser/extensions/e10srollout/install.rdf.in

@@ -10,7 +10,7 @@
 
   <Description about="urn:mozilla:install-manifest">
     <em:id>e10srollout@mozilla.org</em:id>
-    <em:version>1.12</em:version>
+    <em:version>1.13</em:version>
     <em:type>2</em:type>
     <em:bootstrap>true</em:bootstrap>
     <em:multiprocessCompatible>true</em:multiprocessCompatible>