Bug 1760920 - pt 8. Query memory per zone r=jonco

Since the caller usually needs to know the zone anyway, this seems simpler
if we query based on the zone rather than the object.

Differential Revision: https://phabricator.services.mozilla.com/D146677

js/src/jsfriendapi.cpp

@@ -763,9 +763,7 @@ JS_PUBLIC_API JS::Value js::MaybeGetScriptPrivate(JSObject* object) {
   return object->as<ScriptSourceObject>().getPrivate();
 }
 
-JS_PUBLIC_API uint64_t js::GetMemoryUsageForObjectZone(JSObject* obj) {
-  Zone* zone = obj->zone();
-
+JS_PUBLIC_API uint64_t js::GetMemoryUsageForZone(Zone* zone) {
   // We do not include zone->sharedMemoryUseCounts since that's already included
   // in zone->mallocHeapSize.
   return zone->gcHeapSize.bytes() + zone->mallocHeapSize.bytes() +

js/src/jsfriendapi.h

@@ -733,8 +733,8 @@ class MOZ_STACK_CLASS JS_PUBLIC_API AutoAssertNoContentJS {
 };
 
 /**
- * This function reports memory used by a JS object's zone, this includes:
- *  * The size of this object's JS GC zone.
+ * This function reports memory used by a zone in bytes, this includes:
+ *  * The size of this JS GC zone.
  *  * Malloc memory referred to from this zone.
  *  * JIT memory for this zone.
  *
@@ -742,7 +742,7 @@ class MOZ_STACK_CLASS JS_PUBLIC_API AutoAssertNoContentJS {
  * SharedArrayBuffers which may also be referred to from other zones. Adding the
  * memory usage of multiple zones may lead to an over-estimate.
  */
-extern JS_PUBLIC_API uint64_t GetMemoryUsageForObjectZone(JSObject* obj);
+extern JS_PUBLIC_API uint64_t GetMemoryUsageForZone(JS::Zone* zone);
 
 /**
  * This function only reports GC heap memory,

toolkit/components/perfmonitoring/PerformanceUtils.cpp

@@ -145,7 +145,7 @@ RefPtr<MemoryPromise> CollectMemoryInfo(
           // GetMemoryUsageForObjectZone() can will include SharedArrayBuffers
           // which may be shared between multiple zones, this can lead to an
           // over-estimate.
-          jsMemUsed += js::GetMemoryUsageForObjectZone(object);
+          jsMemUsed += js::GetMemoryUsageForZone(zone);
           if (!zonesVisited.add(p, zone)) {
             // OOM.  Let us stop counting memory, we may undercount.
             break;