Stop using chromeos::FakeSessionManagerClient in ArcSessionImpl tests

It's no longer necessary as we've introduced our own abstraction
layer, arc::ArcClientAdapter. This CL injects a fake ArcClientAdapter
implementation to the test fixture to simplify the test. That allows
us to remove all usage of chromeos:: and login_manager:: from the
test, and the test no longer depends on the internals of the ARC
container.

BUG=b:143175953
TEST=try

Change-Id: Ia39f492a94b5698794df423b181ff935b944eec4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2008284Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Yusuke Sato <yusukes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733888}

components/arc/session/arc_session_impl.cc

@@ -99,6 +99,7 @@ class ArcSessionDelegateImpl : public ArcSessionImpl::Delegate {
   void GetLcdDensity(GetLcdDensityCallback callback) override;
   void GetFreeDiskSpace(GetFreeDiskSpaceCallback callback) override;
   version_info::Channel GetChannel() override;
+  std::unique_ptr<ArcClientAdapter> CreateClient() override;
 
  private:
   // Synchronously create a UNIX domain socket. This is designed to run on a
@@ -192,6 +193,10 @@ version_info::Channel ArcSessionDelegateImpl::GetChannel() {
   return channel_;
 }
 
+std::unique_ptr<ArcClientAdapter> ArcSessionDelegateImpl::CreateClient() {
+  return ArcClientAdapter::Create(GetChannel());
+}
+
 // static
 base::ScopedFD ArcSessionDelegateImpl::CreateSocketInternal() {
   auto endpoint = mojo::NamedPlatformChannel({kArcBridgeSocketPath});
@@ -315,7 +320,7 @@ ArcSessionImpl::ArcSessionImpl(std::unique_ptr<Delegate> delegate,
                                chromeos::SchedulerConfigurationManagerBase*
                                    scheduler_configuration_manager)
     : delegate_(std::move(delegate)),
-      client_(ArcClientAdapter::Create(delegate_->GetChannel())),
+      client_(delegate_->CreateClient()),
       scheduler_configuration_manager_(scheduler_configuration_manager) {
   DCHECK(client_);
   client_->AddObserver(this);

components/arc/session/arc_session_impl.h

@@ -169,11 +169,14 @@ class ArcSessionImpl
 
     // Returns the channel for the installation.
     virtual version_info::Channel GetChannel() = 0;
+
+    // Creates and returns a client adapter.
+    virtual std::unique_ptr<ArcClientAdapter> CreateClient() = 0;
   };
 
   ArcSessionImpl(std::unique_ptr<Delegate> delegate,
                  chromeos::SchedulerConfigurationManagerBase*
-                     scheduler_configuration_manager_);
+                     scheduler_configuration_manager);
   ~ArcSessionImpl() override;
 
   // Returns default delegate implementation used for the production.
@@ -183,6 +186,7 @@ class ArcSessionImpl
       version_info::Channel channel);
 
   State GetStateForTesting() { return state_; }
+  ArcClientAdapter* GetClientForTesting() { return client_.get(); }
 
   // ArcSession overrides:
   void StartMiniInstance() override;