Fix the issue that on tablet/unfold, the allapps background color is wrong.

As the new spec, it should use materialColorSurfaceDim for all devices.

Bug: 288493929
Test: manual, before: https://screenshot.googleplex.com/7YxpFGekwm6Gz6N, after: https://screenshot.googleplex.com/44Gr2dBfWSct7FK
Flag: no flag needed.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:aa6612d3731a3e98f716747b0ede473e3bbca161)
Merged-In: Ic33d9a758fe9fbaa0f735c874a545df711a18e2f
Change-Id: Ic33d9a758fe9fbaa0f735c874a545df711a18e2f
diff --git a/src/com/android/launcher3/allapps/ActivityAllAppsContainerView.java b/src/com/android/launcher3/allapps/ActivityAllAppsContainerView.java
index d4140d8..1977704 100644
--- a/src/com/android/launcher3/allapps/ActivityAllAppsContainerView.java
+++ b/src/com/android/launcher3/allapps/ActivityAllAppsContainerView.java
@@ -43,7 +43,6 @@
 import android.util.FloatProperty;
 import android.util.Log;
 import android.util.SparseArray;
-import android.util.TypedValue;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
@@ -272,9 +271,8 @@
                 0,
                 0 // Bottom left
         };
-        final TypedValue value = new TypedValue();
-        getContext().getTheme().resolveAttribute(android.R.attr.colorBackground, value, true);
-        mBottomSheetBackgroundColor = value.data;
+        mBottomSheetBackgroundColor =
+                Themes.getAttrColor(getContext(), R.attr.materialColorSurfaceDim);
         updateBackgroundVisibility(mActivityContext.getDeviceProfile());
         mSearchUiManager.initializeSearch(this);
     }