Clean up framework brightness system

Remove brightness_float setting.
Delete unused code.
Use display manager sync root for BrightnessSetting

Bug: 191472484
Test: atest com.android.server.display

Change-Id: I0cc722949081ba5a3aaa9f7fa4ff4e874578925b

1 files changed, 10 insertions, 0 deletions

diff --git a/core/java/com/android/internal/display/BrightnessSynchronizer.java b/core/java/com/android/internal/display/BrightnessSynchronizer.java
index 19183b8eb9e7..c9a9e51dceed 100644
--- a/core/java/com/android/internal/display/BrightnessSynchronizer.java
+++ b/core/java/com/android/internal/display/BrightnessSynchronizer.java
@@ -154,10 +154,20 @@ public class BrightnessSynchronizer {
         }
     }
 
+    /**
+     * Gets the stored screen brightness float value from the display brightness setting.
+     * @return brightness
+     */
     private float getScreenBrightnessFloat() {
         return mDisplayManager.getBrightness(Display.DEFAULT_DISPLAY);
     }
 
+    /**
+     * Gets the stored screen brightness int from the system settings.
+     * @param context for accessing settings
+     *
+     * @return brightness
+     */
     private static int getScreenBrightnessInt(Context context) {
         return Settings.System.getIntForUser(context.getContentResolver(),
                 Settings.System.SCREEN_BRIGHTNESS, PowerManager.BRIGHTNESS_INVALID,