Bug 1626570 - Improve handling of copying arrays in ipc/. r=nika

Differential Revision: https://phabricator.services.mozilla.com/D73679

ipc/chromium/src/base/histogram.h

@@ -70,7 +70,7 @@ class Histogram {
   // Initialize maximum number of buckets in histograms as 16,384.
   static const size_t kBucketCount_MAX;
 
-  typedef nsTArray<Count> Counts;
+  typedef CopyableTArray<Count> Counts;
   typedef const Sample* Ranges;
 
   // These enums are used to facilitate deserialization of renderer histograms

ipc/glue/BackgroundImpl.cpp

@@ -1555,7 +1555,7 @@ ParentImpl::ForceCloseBackgroundActorsRunnable::Run() {
 
   if (!mActorArray->IsEmpty()) {
     // Copy the array since calling Close() could mutate the actual array.
-    nsTArray<ParentImpl*> actorsToClose(*mActorArray);
+    nsTArray<ParentImpl*> actorsToClose(mActorArray->Clone());
 
     for (uint32_t index = 0; index < actorsToClose.Length(); index++) {
       actorsToClose[index]->Close();