Initial changes to support blur

- Add a new controller to update the background blur on either the
  launcher or app surfaces based on state or transition

Bug: 149792636

Change-Id: I6103cd3d53a00c8025558dd49bb73137e2980014
diff --git a/src/com/android/launcher3/LauncherState.java b/src/com/android/launcher3/LauncherState.java
index 36440c9..62b8927 100644
--- a/src/com/android/launcher3/LauncherState.java
+++ b/src/com/android/launcher3/LauncherState.java
@@ -41,6 +41,7 @@
 import static com.android.launcher3.testing.TestProtocol.QUICK_SWITCH_STATE_ORDINAL;
 import static com.android.launcher3.testing.TestProtocol.SPRING_LOADED_STATE_ORDINAL;
 
+import android.content.Context;
 import android.view.View;
 import android.view.animation.Interpolator;
 
@@ -269,6 +270,14 @@
         return 0;
     }
 
+    /**
+     * The amount of blur to apply to the background of either the app or Launcher surface in this
+     * state.
+     */
+    public int getBackgroundBlurRadius(Context context) {
+        return 0;
+    }
+
     public String getDescription(Launcher launcher) {
         return launcher.getWorkspace().getCurrentPageDescription();
     }