Add support for having more hotseat icons in the DB than we show

Split InvariantDeviceProfile#numHotseatIcons into two variables:
numDatabaseHotseatIcons and numShownHotseatIcons. These are generally
the same, but different DisplayOptions within the same GridOption
can choose to show different numbers of hotseat icons while sharing
the same database.

numDatabaseHotseatIcons is used for all reading/writing/migrating
purposes, while numShownHotseatIcons determines how many Hotseat
icons to show in the UI.

Test: Existing tests pass, added two new migration tests
Bug: 184789479
Bug: 171917176

Change-Id: I54583504f61a47a4444b6a637ebb7e3ab31528b7
diff --git a/src/com/android/launcher3/DeviceProfile.java b/src/com/android/launcher3/DeviceProfile.java
index 35b0f27..985a445 100644
--- a/src/com/android/launcher3/DeviceProfile.java
+++ b/src/com/android/launcher3/DeviceProfile.java
@@ -137,6 +137,7 @@
     public int folderChildDrawablePaddingPx;
 
     // Hotseat
+    public final int numShownHotseatIcons;
     public int hotseatCellHeightPx;
     // In portrait: size = height, in landscape: size = width
     public int hotseatBarSizePx;
@@ -293,6 +294,7 @@
 
         workspaceCellPaddingXPx = res.getDimensionPixelSize(R.dimen.dynamic_grid_cell_padding_x);
 
+        numShownHotseatIcons = inv.numShownHotseatIcons;
         hotseatBarTopPaddingPx =
                 res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_top_padding);
         hotseatBarBottomPaddingPx = (isTallDevice ? 0
@@ -735,7 +737,7 @@
             // for this, we pad the left and right of the hotseat with half of the difference of a
             // workspace cell vs a hotseat cell.
             float workspaceCellWidth = (float) widthPx / inv.numColumns;
-            float hotseatCellWidth = (float) widthPx / inv.numHotseatIcons;
+            float hotseatCellWidth = (float) widthPx / inv.numShownHotseatIcons;
             int hotseatAdjustment = Math.round((workspaceCellWidth - hotseatCellWidth) / 2);
             mHotseatPadding.set(
                     hotseatAdjustment + workspacePadding.left + cellLayoutPaddingLeftRightPx