手机灭屏速度优化

思路

由于灭屏场景下，为了性能需要适当的调整一些动画参数，对用户体验上影响不大。
故可以以下思路
1.缩短动画时间
2.去除灭屏前动画

修改DisplayPowerController

/frameworks/base/services/core/java/com/android/server/display/DisplayPowerController.java

--- a+++ b/frameworks/base/services/core/java/com/android/server/display/DisplayPowerController.java@@ -100,7 +100,10 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call//  缩短动画时间-    private static final int COLOR_FADE_OFF_ANIMATION_DURATION_MILLIS = 400;+    private static final int COLOR_FADE_OFF_ANIMATION_DURATION_MILLIS = 20;     private static final int MSG_UPDATE_POWER_STATE = 1;     private static final int MSG_PROXIMITY_SENSOR_DEBOUNCED = 2;@@ -1092,9 +1095,12 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call                 mPendingScreenOff = false;                 mPowerState.dismissColorFadeResources();             } else if (performScreenOffTransition-                    && mPowerState.prepareColorFade(mContext,+                    /*&& mPowerState.prepareColorFade(mContext,                             mColorFadeFadesConfig ?-                                    ColorFade.MODE_FADE : ColorFade.MODE_COOL_DOWN)+                                    ColorFade.MODE_FADE : ColorFade.MODE_COOL_DOWN) */                     && mPowerState.getScreenState() != Display.STATE_OFF) {                 // Perform the screen off animation.                 mColorFadeOffAnimator.start();