Let PrefRegistry::OnPrefRegistered take a std::string_view.

This CL is part of transitioning PrefRegistry to use std::string_view.
The CL contains no functional changes and incurs no extra (string)
copies in production code.

Bug: 348307659
Change-Id: I03e2546cce47f8b286efa708b4555830cabe93ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5643972
Reviewed-by: Dominic Battré <battre@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Jan Keitel <jkeitel@google.com>
Cr-Commit-Position: refs/heads/main@{#1317289}

components/pref_registry/pref_registry_syncable.cc

@@ -4,6 +4,8 @@
 
 #include "components/pref_registry/pref_registry_syncable.h"
 
+#include <string_view>
+
 #include "base/files/file_path.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
@@ -32,7 +34,7 @@ void PrefRegistrySyncable::SetSyncableRegistrationCallback(
   callback_ = std::move(cb);
 }
 
-void PrefRegistrySyncable::OnPrefRegistered(const std::string& path,
+void PrefRegistrySyncable::OnPrefRegistered(std::string_view path,
                                             uint32_t flags) {
   // Tests that |flags| does not contain both SYNCABLE_PREF and
   // SYNCABLE_PRIORITY_PREF flags at the same time.

components/pref_registry/pref_registry_syncable.h

@@ -7,7 +7,7 @@
 
 #include <stdint.h>
 
-#include <string>
+#include <string_view>
 
 #include "base/functional/callback.h"
 #include "build/chromeos_buildflags.h"
@@ -64,7 +64,7 @@ class PrefRegistrySyncable : public PrefRegistrySimple {
   };
 
   using SyncableRegistrationCallback =
-      base::RepeatingCallback<void(const std::string& path, uint32_t flags)>;
+      base::RepeatingCallback<void(std::string_view path, uint32_t flags)>;
 
   PrefRegistrySyncable();
 
@@ -88,8 +88,7 @@ class PrefRegistrySyncable : public PrefRegistrySimple {
   ~PrefRegistrySyncable() override;
 
   // PrefRegistrySimple overrides.
-  void OnPrefRegistered(const std::string& path,
-                        uint32_t flags) override;
+  void OnPrefRegistered(std::string_view path, uint32_t flags) override;
 
   SyncableRegistrationCallback callback_;
 };

components/prefs/pref_registry.cc

@@ -5,6 +5,8 @@
 #include "components/prefs/pref_registry.h"
 
 #include <ostream>
+#include <string>
+#include <string_view>
 #include <utility>
 
 #include "base/check_op.h"
@@ -80,5 +82,4 @@ void PrefRegistry::RegisterForeignPref(const std::string& path) {
   DCHECK(inserted);
 }
 
-void PrefRegistry::OnPrefRegistered(const std::string& path,
-                                    uint32_t flags) {}
+void PrefRegistry::OnPrefRegistered(std::string_view path, uint32_t flags) {}

components/prefs/pref_registry.h

@@ -8,6 +8,8 @@
 #include <stdint.h>
 
 #include <set>
+#include <string>
+#include <string_view>
 #include <unordered_map>
 
 #include "base/memory/ref_counted.h"
@@ -100,8 +102,7 @@ class COMPONENTS_PREFS_EXPORT PrefRegistry
                           uint32_t flags);
 
   // Allows subclasses to hook into pref registration.
-  virtual void OnPrefRegistered(const std::string& path,
-                                uint32_t flags);
+  virtual void OnPrefRegistered(std::string_view path, uint32_t flags);
 
   scoped_refptr<DefaultPrefStore> defaults_;
 

components/sync_preferences/pref_service_syncable.cc

@@ -280,10 +280,9 @@ void PrefServiceSyncable::RemoveSyncedPrefObserver(
 #endif
 }
 
-void PrefServiceSyncable::AddRegisteredSyncablePreference(
-    const std::string& path,
-    uint32_t flags) {
-  DCHECK(FindPreference(path));
+void PrefServiceSyncable::AddRegisteredSyncablePreference(std::string_view path,
+                                                          uint32_t flags) {
+  DCHECK(FindPreference(std::string(path)));
   if (flags & user_prefs::PrefRegistrySyncable::SYNCABLE_PREF) {
     pref_sync_associator_.RegisterPref(path);
     return;

components/sync_preferences/pref_service_syncable.h

@@ -9,6 +9,7 @@
 
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include "base/functional/callback_forward.h"
@@ -122,7 +123,7 @@ class PrefServiceSyncable : public PrefService,
 
   void ConnectAssociatorsAndRegisterPreferences();
 
-  void AddRegisteredSyncablePreference(const std::string& path, uint32_t flags);
+  void AddRegisteredSyncablePreference(std::string_view path, uint32_t flags);
 
   // PrefServiceForAssociator:
   base::Value::Type GetRegisteredPrefType(