Fix non-compliant rvalue ref code in mac/update_service_proxy_test.mm.

This CL fixes two minor coding style issues.

https://google.github.io/styleguide/cppguide.html#Rvalue_references

According to the coding style, rvalue refs can only be used in a
couple of scenarios, and they do not include the following:

1. base::OnceClosure&& done_cb
The idiomatic way is to declare base::OnceClosure function parameters
by value.

2. StateChangeTestEngine::StateChangeTestEngine(
      std::vector<StatePair>&& state_vec)
    : state_seq_(state_vec) {}
This ctor is not one of the cases where overloads on rvalue ref are
allowed.

Also, the code on trunk has a minor bug: because move semantics are not
passed through, std::move needs to be called even though `state_vec`
is a rvalue reference. Otherwise, the member initialization is still
going to be a copy instead of a move.


Bug: 1164718
Change-Id: I3d63cb6bb837121e640381ce1ff0ae96ce08d161
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2619964Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Sorin Jianu <sorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843696}

chrome/updater/mac/update_service_proxy_test.mm

@@ -55,7 +55,7 @@ class StateChangeTestEngine {
   // Construct a StateChangeTestEngine that will issue the given states in
   // the given sequence, and verify that it observes the expected items
   // in its callback.
-  StateChangeTestEngine(std::vector<StatePair>&& state_vec);
+  explicit StateChangeTestEngine(std::vector<StatePair> state_vec);
 
   ~StateChangeTestEngine();
 
@@ -73,7 +73,7 @@ class StateChangeTestEngine {
   // of the test - this is intended to be used to send the final reply.
   void StartSimulating(
       base::scoped_nsprotocol<id<CRUUpdateStateObserving>> observer,
-      base::OnceClosure&& done_cb);
+      base::OnceClosure done_cb);
 
  private:
   using vec_size_t = std::vector<StatePair>::size_type;
@@ -123,8 +123,8 @@ class StateChangeTestEngine {
 const StateChangeTestEngine::vec_size_t StateChangeTestEngine::kNotStarted;
 const StateChangeTestEngine::vec_size_t StateChangeTestEngine::kDone;
 
-StateChangeTestEngine::StateChangeTestEngine(std::vector<StatePair>&& state_vec)
-    : state_seq_(state_vec) {}
+StateChangeTestEngine::StateChangeTestEngine(std::vector<StatePair> state_vec)
+    : state_seq_(std::move(state_vec)) {}
 
 StateChangeTestEngine::~StateChangeTestEngine() {
   EXPECT_NE(next_observation_, kNotStarted)
@@ -138,7 +138,7 @@ StateChangeTestEngine::~StateChangeTestEngine() {
 
 void StateChangeTestEngine::StartSimulating(
     base::scoped_nsprotocol<id<CRUUpdateStateObserving>> observer,
-    base::OnceClosure&& done_cb) {
+    base::OnceClosure done_cb) {
   EXPECT_TRUE(callback_prepared_)
       << "TEST ISSUE:  StateChangetestEngine cannot StartSimulating without "
          "Watch()ing for event callbacks";