[ALS logging] Add kPowerAlsLoggingEnabled to control als logging.

Bug: 967934
Change-Id: Ie99ab58537dbdc6473a9fe5f76bf59cb2db5886e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1633689Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Jia Meng <jiameng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664560}

ash/public/cpp/ash_pref_names.cc

@@ -301,6 +301,9 @@ const char kPowerFastSuspendWhenBacklightsForcedOff[] =
 // Boolean controlling whether smart dim model is enabled.
 const char kPowerSmartDimEnabled[] = "power.smart_dim_enabled";
 
+// Boolean controlling whether ALS logging is enabled.
+const char kPowerAlsLoggingEnabled[] = "power.als_logging_enabled";
+
 // |kShelfAlignment| and |kShelfAutoHideBehavior| have a local variant. The
 // local variant is not synced and is used if set. If the local variant is not
 // set its value is set from the synced value (once prefs have been

ash/public/cpp/ash_pref_names.h

@@ -110,6 +110,7 @@ ASH_PUBLIC_EXPORT extern const char
     kPowerForceNonzeroBrightnessForUserActivity[];
 ASH_PUBLIC_EXPORT extern const char kPowerFastSuspendWhenBacklightsForcedOff[];
 ASH_PUBLIC_EXPORT extern const char kPowerSmartDimEnabled[];
+ASH_PUBLIC_EXPORT extern const char kPowerAlsLoggingEnabled[];
 
 ASH_PUBLIC_EXPORT extern const char kShelfAlignment[];
 ASH_PUBLIC_EXPORT extern const char kShelfAlignmentLocal[];

ash/system/power/power_prefs.cc

@@ -123,6 +123,8 @@ void RegisterProfilePrefs(PrefRegistrySimple* registry, bool for_test) {
                                 true, PrefRegistry::PUBLIC);
   registry->RegisterBooleanPref(prefs::kPowerSmartDimEnabled, true,
                                 PrefRegistry::PUBLIC);
+  registry->RegisterBooleanPref(prefs::kPowerAlsLoggingEnabled, false,
+                                PrefRegistry::PUBLIC);
 
   if (for_test) {
     registry->RegisterBooleanPref(prefs::kAllowScreenLock, true,
@@ -445,6 +447,7 @@ void PowerPrefs::ObservePrefs(PrefService* prefs) {
   profile_registrar_->Add(prefs::kPowerSmartDimEnabled, update_callback);
   profile_registrar_->Add(prefs::kPowerFastSuspendWhenBacklightsForcedOff,
                           update_callback);
+  profile_registrar_->Add(prefs::kPowerAlsLoggingEnabled, update_callback);
 
   UpdatePowerPolicyFromPrefs();
 }

ash/system/power/power_prefs_unittest.cc

@@ -526,4 +526,10 @@ TEST_F(PowerPrefsTest, UsbPowerShare) {
   EXPECT_FALSE(power_manager_client()->policy().usb_power_share());
 }
 
+TEST_F(PowerPrefsTest, AlsLoggingEnabled) {
+  PrefService* prefs =
+      Shell::Get()->session_controller()->GetActivePrefService();
+  EXPECT_FALSE(prefs->GetBoolean(prefs::kPowerAlsLoggingEnabled));
+}
+
 }  // namespace ash