Partial revert of "Remove ~MaybeHandle and statically assert that handles are trivially copyable"

Reason: cause Blink regression on Android

Original CL: https://chromium-review.googlesource.com/c/538463/

Bug: chromium:735910
Change-Id: I405e71f6ffeaf9fa467036a6fafa0271a60de9d3
Reviewed-on: https://chromium-review.googlesource.com/593247Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Loo Rong Jie <loorongjie@gmail.com>
Cr-Commit-Position: refs/heads/master@{#46995}

src/base/macros.h

@@ -189,12 +189,6 @@ V8_INLINE Dest bit_cast(Source const& source) {
 // TODO(all) Replace all uses of this macro with static_assert, remove macro.
 #define STATIC_ASSERT(test) static_assert(test, #test)
 
-// TODO(rongjie) Remove this workaround once we require gcc >= 5.0
-#if __GNUG__ && __GNUC__ < 5
-#define IS_TRIVIALLY_COPYABLE(T) __has_trivial_copy(T)
-#else
-#define IS_TRIVIALLY_COPYABLE(T) std::is_trivially_copyable<T>::value
-#endif
 
 // The USE(x, ...) template is used to silence C++ compiler warnings
 // issued for (yet) unused variables (typically parameters).

src/handles.cc

@@ -12,15 +12,6 @@
 namespace v8 {
 namespace internal {
 
-// Handles should be trivially copyable so that they can be efficiently passed
-// by value. If they are not trivially copyable, they cannot be passed in
-// registers.
-static_assert(IS_TRIVIALLY_COPYABLE(HandleBase),
-              "HandleBase should be trivially copyable");
-static_assert(IS_TRIVIALLY_COPYABLE(Handle<Object>),
-              "Handle<Object> should be trivially copyable");
-static_assert(IS_TRIVIALLY_COPYABLE(MaybeHandle<Object>),
-              "MaybeHandle<Object> should be trivially copyable");
 
 #ifdef DEBUG
 bool HandleBase::IsDereferenceAllowed(DereferenceCheckMode mode) const {

src/handles.h

@@ -185,6 +185,7 @@ template <typename T>
 class MaybeHandle final {
  public:
   V8_INLINE MaybeHandle() {}
+  V8_INLINE ~MaybeHandle() {}
 
   // Constructor for handling automatic up casting from Handle.
   // Ex. Handle<JSArray> can be passed when MaybeHandle<Object> is expected.