message: add more metrics to FinalInline
  Summary:
  How many fields got inlined?
  How many fields got removed?
diff: @@ -91,7 +91,8 @@ class FinalInlineImpl {
  return false;
  }
  - void remove_unused_fields() {
  + // returns the number of fields removed
  + size_t remove_unused_fields() {
  std::vector<DexField*> moveable_fields;
  std::vector<DexClass*> smallscope;
  uint32_t aflags = ACC_STATIC | ACC_FINAL;
  @@ -150,6 +151,7 @@ class FinalInlineImpl {
  }),
  sfields.end());
  }
  + return smallscope.size();
  }
  bool check_sget(IRInstruction* opfield) {
  @@ -215,7 +217,8 @@ class FinalInlineImpl {
  }
  }
  - void inline_field_values() {
  + // returns the total number of inlines
  + size_t inline_field_values() {
  std::unordered_set<DexField*> inline_field;
  uint32_t aflags = ACC_STATIC | ACC_FINAL;
  for (auto clazz : m_full_scope) {
  @@ -241,10 +244,12 @@ class FinalInlineImpl {
  }
  }
  - walk_methods_parallel_simple(m_full_scope, [&](DexMethod* m) {
  + return walk_methods_parallel<std::nullptr_t, size_t, Scope>(
  + m_full_scope,
  + [&inline_field, this](std::nullptr_t, DexMethod* m) -> size_t {
  auto* code = m->get_code();
  if (!code) {
  - return;
  + return 0;
  }
  std::vector<FatMethod::iterator> rewrites;
  auto ii = InstructionIterable(code);
  @@ -273,7 +278,11 @@ class FinalInlineImpl {
  code->insert_before(it, newopcode);
  code->remove_opcode(it);
  }
  - });
  + return rewrites.size();
  + },
  + [](size_t a, size_t b) { return a + b; }, // output reducer
  + [](int) { return nullptr; } // data initializer. not needed
  + );
  }
  /*
  @@ -618,7 +627,7 @@ class FinalInlineImpl {
  }
  }
  };
  -}
  +} // namespace
  size_t FinalInlinePass::propagate_constants_for_test(Scope& scope,
  bool inline_string_fields,
  @@ -659,8 +668,11 @@ void FinalInlinePass::run_pass(DexStoresVector& stores,
  mgr.incr_metric("encodable_clinits_replaced", nreplaced);
  }
  - impl.inline_field_values();
  - impl.remove_unused_fields();
  + size_t num_finals_inlined = impl.inline_field_values();
  + size_t num_removed_fields = impl.remove_unused_fields();
  +
  + mgr.incr_metric("num_finals_inlined", num_finals_inlined);
  + mgr.incr_metric("num_removed_fields", num_removed_fields);
  }
  void FinalInlinePass::inline_fields(const Scope& scope) {
  