Bug 1863867 - Add expriment targeting based on archiecture bits r=barret

Differential Revision: https://phabricator.services.mozilla.com/D193159

browser/components/newtab/content-src/asrouter/docs/targeting-attributes.md

@@ -11,6 +11,7 @@ Please note that some targeting attributes require stricter controls on the tele
 * [activeNotifications](#activenotifications)
 * [addonsInfo](#addonsinfo)
 * [addressesSaved](#addressessaved)
+* [archBits](#archbits)
 * [attachedFxAOAuthClients](#attachedfxaoauthclients)
 * [attributionData](#attributiondata)
 * [backgroundTaskName](#backgroundtaskname)
@@ -588,6 +589,16 @@ addressesSaved > 1
 declare const addressesSaved: Promise<number>
 ```
 
+### `archBits`
+
+The number of bits used to represent a pointer in this build.
+
+#### Definition
+
+```ts
+declare const archBits: number;
+```
+
 ### `xpinstallEnabled`
 
 Pref used by system administrators to disallow add-ons from installed altogether.

browser/components/newtab/lib/ASRouterTargeting.jsm

@@ -1012,6 +1012,19 @@ const TargetingGetters = {
       height: window?.screen.availHeight,
     };
   },
+
+  get archBits() {
+    let bits = null;
+    try {
+      bits = Services.sysinfo.getProperty("archbits", null);
+    } catch (_e) {
+      // getProperty can throw if the memsize does not exist
+    }
+    if (bits) {
+      bits = Number(bits);
+    }
+    return bits;
+  },
 };
 
 const ASRouterTargeting = {

browser/components/newtab/test/browser/browser_asrouter_targeting.js

@@ -1693,3 +1693,9 @@ add_task(async function check_primaryResolution() {
     "Height property should return a number"
   );
 });
+
+add_task(async function check_archBits() {
+  const bits = ASRouterTargeting.Environment.archBits;
+  is(typeof bits, "number", "archBits should be a number");
+  ok(bits === 32 || bits === 64, "archBits is either 32 or 64");
+});

xpcom/base/nsSystemInfo.cpp

@@ -974,6 +974,12 @@ nsresult nsSystemInfo::Init() {
   SetUint64Property(u"memsize"_ns, PR_GetPhysicalMemorySize());
   SetUint32Property(u"umask"_ns, nsSystemInfo::gUserUmask);
 
+#ifdef HAVE_64BIT_BUILD
+  SetUint32Property(u"archbits"_ns, 64);
+#else
+  SetUint32Property(u"archbits"_ns, 32);
+#endif
+
   uint64_t virtualMem = 0;
 
 #if defined(XP_WIN)