Use SupportsWeakPtr<SmbProviderClient>

This change switches SmbProviderClient to using base::SupportsWeakPtr
and SmbProviderClientImpl to using a helper class that wraps it
instead of a manually implemented WeakPtrFactory.

Bug: chromium:757625
Change-Id: I18f3b04c18ba28bdf8bf9c356b3ebeb98d546cd3
Reviewed-on: https://chromium-review.googlesource.com/956417
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542951}

chromeos/dbus/smb_provider_client.cc

@@ -58,7 +58,7 @@ bool ParseDeleteList(const base::ScopedFD& fd,
 
 class SmbProviderClientImpl : public SmbProviderClient {
  public:
-  SmbProviderClientImpl() : weak_ptr_factory_(this) {}
+  SmbProviderClientImpl() = default;
 
   ~SmbProviderClientImpl() override {}
 
@@ -260,9 +260,9 @@ class SmbProviderClientImpl : public SmbProviderClient {
   void CallMethod(dbus::MethodCall* method_call,
                   CallbackHandler handler,
                   Callback callback) {
-    proxy_->CallMethod(method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
-                       base::BindOnce(handler, weak_ptr_factory_.GetWeakPtr(),
-                                      base::Passed(callback)));
+    proxy_->CallMethod(
+        method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::BindOnce(handler, GetWeakPtr(), base::Passed(callback)));
   }
 
   // Calls the D-Bus method |name|, passing the |protobuf| as an argument.
@@ -284,7 +284,7 @@ class SmbProviderClientImpl : public SmbProviderClient {
     proxy_->CallMethod(
         method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
         base::BindOnce(&SmbProviderClientImpl::HandleDefaultCallback,
-                       weak_ptr_factory_.GetWeakPtr(), method_call->GetMember(),
+                       GetWeakPtr(), method_call->GetMember(),
                        base::Passed(callback)));
   }
 
@@ -413,11 +413,11 @@ class SmbProviderClientImpl : public SmbProviderClient {
     std::move(callback).Run(error, proto);
   }
 
-  dbus::ObjectProxy* proxy_ = nullptr;
+  base::WeakPtr<SmbProviderClientImpl> GetWeakPtr() {
+    return base::AsWeakPtr(this);
+  }
 
-  // Note: This should remain the last member so it'll be destroyed and
-  // invalidate its weak pointers before any other members are destroyed.
-  base::WeakPtrFactory<SmbProviderClientImpl> weak_ptr_factory_;
+  dbus::ObjectProxy* proxy_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(SmbProviderClientImpl);
 };

chromeos/dbus/smb_provider_client.h

@@ -8,6 +8,7 @@
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_file.h"
+#include "base/memory/weak_ptr.h"
 #include "chromeos/chromeos_export.h"
 #include "chromeos/dbus/dbus_client.h"
 #include "chromeos/dbus/smbprovider/directory_entry.pb.h"
@@ -19,7 +20,9 @@ namespace chromeos {
 // SmbProviderClient is used to communicate with the org.chromium.SmbProvider
 // service. All methods should be called from the origin thread (UI thread)
 // which initializes the DBusThreadManager instance.
-class CHROMEOS_EXPORT SmbProviderClient : public DBusClient {
+class CHROMEOS_EXPORT SmbProviderClient
+    : public DBusClient,
+      public base::SupportsWeakPtr<SmbProviderClient> {
  public:
   using GetMetdataEntryCallback =
       base::OnceCallback<void(smbprovider::ErrorType error,