Bug 1626587 - Part 4: Remove mozilla::IsPod for HashMapEntry. r=jwalden

The `mozilla::IsPod<HashMapEntry` specialisation was only needed for the static
assertions in "js/src/frontend/NameCollections.h". Part 3 removed those, so we
can now also remove `mozilla::IsPod<HashMapEntry`.

Drive-by change:
- Remove no longer needed "mozilla/PodOperations.h" include in mfbt/HashTable.h.
- And then fix up previously transitively included files for RootingAPI.h,
  jsfriendapi.h, and Bench.cpp.

Differential Revision: https://phabricator.services.mozilla.com/D69201

js/public/RootingAPI.h

@@ -9,6 +9,7 @@
 
 #include "mozilla/Attributes.h"
 #include "mozilla/DebugOnly.h"
+#include "mozilla/EnumeratedArray.h"
 #include "mozilla/GuardObjects.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/Maybe.h"

js/src/jsfriendapi.h

@@ -11,6 +11,7 @@
 #include "mozilla/Casting.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/MemoryReporting.h"
+#include "mozilla/PodOperations.h"
 #include "mozilla/UniquePtr.h"
 
 #include "jspubtd.h"

mfbt/HashTable.h

@@ -88,9 +88,7 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Opaque.h"
 #include "mozilla/OperatorNewExtensions.h"
-#include "mozilla/PodOperations.h"
 #include "mozilla/ReentrancyGuard.h"
-#include "mozilla/TypeTraits.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/WrappingOperations.h"
 
@@ -926,10 +924,6 @@ class HashMapEntry {
   void operator=(const HashMapEntry&) = delete;
 };
 
-template <typename K, typename V>
-struct IsPod<HashMapEntry<K, V>>
-    : std::integral_constant<bool, IsPod<K>::value && IsPod<V>::value> {};
-
 namespace detail {
 
 template <class T, class HashPolicy, class AllocPolicy>

xpcom/rust/gtest/bench-collections/Bench.cpp

@@ -48,6 +48,7 @@
 #include "gtest/gtest.h"
 #include "gtest/MozGTestBench.h"  // For MOZ_GTEST_BENCH
 #include "mozilla/AllocPolicy.h"
+#include "mozilla/ArrayUtils.h"
 #include "mozilla/HashFunctions.h"
 #include "mozilla/HashTable.h"
 #include "mozilla/StaticMutex.h"