scanning: Pass uuid and name by const reference

Since there's no benefit to passing uuid and device_name by value in
LorgnetteManagerClientImpl, pass them by const reference.

Bug: None
Change-Id: I7594cc938d2c1180eeb172b8c71ac0ee967f1d29
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442501
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Auto-Submit: Jesse Schettler <jschettler@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812824}

chromeos/dbus/fake_lorgnette_manager_client.cc

@@ -34,7 +34,7 @@ void FakeLorgnetteManagerClient::GetScannerCapabilities(
 }
 
 void FakeLorgnetteManagerClient::StartScan(
-    std::string device_name,
+    const std::string& device_name,
     const lorgnette::ScanSettings& settings,
     VoidDBusMethodCallback completion_callback,
     base::RepeatingCallback<void(std::string)> page_callback,

chromeos/dbus/fake_lorgnette_manager_client.h

@@ -30,7 +30,7 @@ class COMPONENT_EXPORT(CHROMEOS_DBUS) FakeLorgnetteManagerClient
   void GetScannerCapabilities(
       const std::string& device_name,
       DBusMethodCallback<lorgnette::ScannerCapabilities> callback) override;
-  void StartScan(std::string device_name,
+  void StartScan(const std::string& device_name,
                  const lorgnette::ScanSettings& settings,
                  VoidDBusMethodCallback completion_callback,
                  base::RepeatingCallback<void(std::string)> page_callback,

chromeos/dbus/lorgnette_manager_client.cc

@@ -66,7 +66,7 @@ class LorgnetteManagerClientImpl : public LorgnetteManagerClient {
   }
 
   // LorgnetteManagerClient override.
-  void StartScan(std::string device_name,
+  void StartScan(const std::string& device_name,
                  const lorgnette::ScanSettings& settings,
                  VoidDBusMethodCallback completion_callback,
                  base::RepeatingCallback<void(std::string)> page_callback,
@@ -266,7 +266,7 @@ class LorgnetteManagerClientImpl : public LorgnetteManagerClient {
   }
 
   // Called when scan data read is completed.
-  void OnScanDataCompleted(std::string uuid,
+  void OnScanDataCompleted(const std::string& uuid,
                            bool more_pages,
                            base::Optional<std::string> data) {
     DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);

chromeos/dbus/lorgnette_manager_client.h

@@ -50,7 +50,7 @@ class COMPONENT_EXPORT(CHROMEOS_DBUS) LorgnetteManagerClient
   // If |progress_callback| is provided, it will be called as scan progress
   // increases. The progress will be passed as a value from 0-100.
   virtual void StartScan(
-      std::string device_name,
+      const std::string& device_name,
       const lorgnette::ScanSettings& settings,
       VoidDBusMethodCallback completion_callback,
       base::RepeatingCallback<void(std::string)> page_callback,