Add back screenshot button to Launcher3

- Also make spacing between buttons always 36dp
- Updated screenshot button image for Launcher3

Fix: 208384949
Test: Start overview in Launcher3WithQuickStep, test screenshot button is working
Change-Id: Ieb60ce134813202c1d14137fff0a131e1f5f8c96
diff --git a/src/com/android/launcher3/DeviceProfile.java b/src/com/android/launcher3/DeviceProfile.java
index ff19918..85d8247 100644
--- a/src/com/android/launcher3/DeviceProfile.java
+++ b/src/com/android/launcher3/DeviceProfile.java
@@ -187,6 +187,7 @@
     public final int overviewActionsMarginThreeButtonPx;
     public final int overviewActionsTopMarginGesturePx;
     public final int overviewActionsBottomMarginGesturePx;
+    public final int overviewActionsButtonSpacing;
     public int overviewPageSpacing;
     public int overviewRowSpacing;
     public int overviewGridSideMargin;
@@ -377,10 +378,14 @@
                 overviewActionsBottomMarginGesturePx = res.getDimensionPixelSize(
                         R.dimen.overview_actions_bottom_margin_gesture_grid_portrait);
             }
+            overviewActionsButtonSpacing = res.getDimensionPixelSize(
+                    R.dimen.overview_actions_button_spacing_grid);
         } else {
             overviewActionsTopMarginGesturePx = res.getDimensionPixelSize(
                     R.dimen.overview_actions_margin_gesture);
             overviewActionsBottomMarginGesturePx = overviewActionsTopMarginGesturePx;
+            overviewActionsButtonSpacing = res.getDimensionPixelSize(
+                    R.dimen.overview_actions_button_spacing);
         }
         overviewActionsMarginThreeButtonPx = res.getDimensionPixelSize(
                 R.dimen.overview_actions_margin_three_button);