Fix some taskbar stashing issues

- Don't allow long press to stash between taskbar icons
- Ensure taskbar_icon_touch_size is respected; previously it wasn't, because BubbleTextView@shouldIgnoreTouchDown() was returning true in the padding region. For taskbar, we want the whole icon size to be touchable.
- Cancel long press when passing touch slop to avoid swipe down being detected as long press

Test: long press on taskbar background, both between icons and not; swipe down on taskbar
Fixes: 198305464
Change-Id: I36f1d792e91da9a3bf57a2bef1e974b299c4e25c
diff --git a/src/com/android/launcher3/BubbleTextView.java b/src/com/android/launcher3/BubbleTextView.java
index 02ec5e8..e52d1be 100644
--- a/src/com/android/launcher3/BubbleTextView.java
+++ b/src/com/android/launcher3/BubbleTextView.java
@@ -409,6 +409,10 @@
      * Returns true if the touch down at the provided position be ignored
      */
     protected boolean shouldIgnoreTouchDown(float x, float y) {
+        if (mDisplay == DISPLAY_TASKBAR) {
+            // Allow touching within padding on taskbar, given icon sizes are smaller.
+            return false;
+        }
         return y < getPaddingTop()
                 || x < getPaddingLeft()
                 || y > getHeight() - getPaddingBottom()