[Night Light] Backend ui::Layer work

ui/compositor/layer_animation_element.h

Index: ui/compositor/layer_animation_element.h
diff --git a/ui/compositor/layer_animation_element.h b/ui/compositor/layer_animation_element.h
index 664468e3bc17ca08f1d10947cb135c13f4bf6f4c..d4f248dece54250bfe1f7ffd33c807996392023c 100644
--- a/ui/compositor/layer_animation_element.h
+++ b/ui/compositor/layer_animation_element.h
@@ -45,10 +45,11 @@ class COMPOSITOR_EXPORT LayerAnimationElement {
     BRIGHTNESS = (1 << 4),
     GRAYSCALE = (1 << 5),
     COLOR = (1 << 6),
+    TEMPERATURE = (1 << 7),
 
     // Used when iterating over properties.
     FIRST_PROPERTY = TRANSFORM,
-    SENTINEL = (1 << 7)
+    SENTINEL = (1 << 8)
   };
 
   static AnimatableProperty ToAnimatableProperty(
@@ -66,6 +67,7 @@ class COMPOSITOR_EXPORT LayerAnimationElement {
     float brightness;
     float grayscale;
     SkColor color;
+    float temperature;
   };
 
   typedef uint32_t AnimatableProperties;
@@ -135,6 +137,12 @@ class COMPOSITOR_EXPORT LayerAnimationElement {
       SkColor color,
       base::TimeDelta duration);
 
+  // Creates an element that transitions to the given color temperature. The
+  // caller owns the return value.
+  static std::unique_ptr<LayerAnimationElement> CreateTemperatureElement(
+      float temperature,
+      base::TimeDelta duration);
+
   // Sets the start time for the animation. This must be called before the first
   // call to {Start, IsFinished}. Once the animation is finished, this must
   // be called again in order to restart the animation.