Fix TaskViewTouchController crash in seascape

Previously, we were using scroll direction POSITIVE as a catch all
to mean "up" but in seascape, we actually want NEGATIVE. Added
getUpDirection() to capture that. Tried to clarify the code a bit
by putting all the methods used solely by TaskViewTouchController
together with documentation. It's still pretty confusing and feels
redundant, but couldn't think of an obvious way to simplify.

Test: Swipe up and down on a task in all permutations of:
- 3 button mode
- Gesture navigation
- Portrait
- Landscape
- Seascape
- LTR
- RTL
- Home rotation allowed
- Home rotation disallowed

Fixes: 174009771
Fixes: 173567204
Change-Id: Id0f8d6f4365d888eb46182d8544d18206795dfb8

src/com/android/launcher3/touch/SeascapePagedViewHandler.java

@@ -16,6 +16,8 @@
 
 package com.android.launcher3.touch;
 
+import static com.android.launcher3.touch.SingleAxisSwipeDetector.HORIZONTAL;
+
 import android.content.res.Resources;
 import android.graphics.PointF;
 import android.graphics.Rect;
@@ -32,11 +34,6 @@ public class SeascapePagedViewHandler extends LandscapePagedViewHandler {
         return -1;
     }
 
-    @Override
-    public int getTaskDragDisplacementFactor(boolean isRtl) {
-        return isRtl ? -1 : 1;
-    }
-
     @Override
     public boolean getRecentsRtlSetting(Resources resources) {
         return Utilities.isRtl(resources);
@@ -52,11 +49,6 @@ public class SeascapePagedViewHandler extends LandscapePagedViewHandler {
         return Surface.ROTATION_270;
     }
 
-    @Override
-    public boolean isGoingUp(float displacement, boolean isRtl) {
-        return isRtl ? displacement > 0 : displacement < 0;
-    }
-
     @Override
     public void adjustFloatingIconStartVelocity(PointF velocity) {
         float oldX = velocity.x;
@@ -78,4 +70,29 @@ public class SeascapePagedViewHandler extends LandscapePagedViewHandler {
     public int getDistanceToBottomOfRect(DeviceProfile dp, Rect rect) {
         return dp.widthPx - rect.right;
     }
+
+    /* ---------- The following are only used by TaskViewTouchHandler. ---------- */
+
+    @Override
+    public SingleAxisSwipeDetector.Direction getUpDownSwipeDirection() {
+        return HORIZONTAL;
+    }
+
+    @Override
+    public int getUpDirection(boolean isRtl) {
+        return isRtl ? SingleAxisSwipeDetector.DIRECTION_POSITIVE
+                : SingleAxisSwipeDetector.DIRECTION_NEGATIVE;
+    }
+
+    @Override
+    public boolean isGoingUp(float displacement, boolean isRtl) {
+        return isRtl ? displacement > 0 : displacement < 0;
+    }
+
+    @Override
+    public int getTaskDragDisplacementFactor(boolean isRtl) {
+        return isRtl ? -1 : 1;
+    }
+
+    /* -------------------- */
 }