Introduce scrim state for bubbles

When bubbles are expanded we'll want to put a scrim behind them, this
is the scrim state we'll use.

Super simple test to check that alpha / visibility state of scrims
are as expected

Test: atest frameworks/base/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
Bug: 111236845
Change-Id: I1ee8ff9e7ce35aae692cf75a912106255e0e9b5a

packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimState.java

@@ -186,6 +186,20 @@ public enum ScrimState {
                 mBlankScreen = false;
             }
         }
+    },
+
+    /**
+     * Unlocked with a bubble expanded.
+     */
+    BUBBLE_EXPANDED(7) {
+        @Override
+        public void prepare(ScrimState previousState) {
+            mCurrentInFrontTint = Color.TRANSPARENT;
+            mCurrentBehindTint = Color.TRANSPARENT;
+            mAnimationDuration = ScrimController.ANIMATION_DURATION;
+            mCurrentBehindAlpha = ScrimController.GRADIENT_SCRIM_ALPHA_BUSY;
+            mBlankScreen = false;
+        }
     };
 
     boolean mBlankScreen = false;

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java

@@ -262,6 +262,19 @@ public class ScrimControllerTest extends SysuiTestCase {
         assertScrimVisibility(VISIBILITY_FULLY_TRANSPARENT, VISIBILITY_SEMI_TRANSPARENT);
     }
 
+    @Test
+    public void transitionToBubbleExpanded() {
+        mScrimController.transitionTo(ScrimState.BUBBLE_EXPANDED);
+        mScrimController.finishAnimationsImmediately();
+
+        // Front scrim should be transparent
+        Assert.assertEquals(ScrimController.VISIBILITY_FULLY_TRANSPARENT,
+                mScrimInFront.getViewAlpha(), 0.0f);
+        // Back scrim should be visible
+        Assert.assertEquals(ScrimController.GRADIENT_SCRIM_ALPHA_BUSY,
+                mScrimBehind.getViewAlpha(), 0.0f);
+    }
+
     @Test
     public void scrimStateCallback() {
         mScrimController.transitionTo(ScrimState.UNLOCKED);