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/LandscapePagedViewHandler.java

@@ -74,11 +74,6 @@ public class LandscapePagedViewHandler implements PagedOrientationHandler {
         out.screenCenter = insets.top + view.getPaddingTop() + out.scroll + out.halfPageSize;
     }
 
-    @Override
-    public boolean isGoingUp(float displacement, boolean isRtl) {
-        return isRtl ? displacement < 0 : displacement > 0;
-    }
-
     @Override
     public boolean isLayoutNaturalToLauncher() {
         return false;
@@ -214,11 +209,6 @@ public class LandscapePagedViewHandler implements PagedOrientationHandler {
         return view.getHeight() - view.getPaddingBottom() - insets.bottom;
     }
 
-    @Override
-    public SingleAxisSwipeDetector.Direction getOppositeSwipeDirection() {
-        return HORIZONTAL;
-    }
-
     @Override
     public int getPrimaryTranslationDirectionFactor() {
         return -1;
@@ -228,11 +218,6 @@ public class LandscapePagedViewHandler implements PagedOrientationHandler {
         return 1;
     }
 
-    @Override
-    public int getTaskDragDisplacementFactor(boolean isRtl) {
-        return isRtl ? 1 : -1;
-    }
-
     @Override
     public float getTaskMenuX(float x, View thumbnailView) {
         return thumbnailView.getMeasuredWidth() + x;
@@ -261,6 +246,31 @@ public class LandscapePagedViewHandler implements PagedOrientationHandler {
         lp.weight = 1;
     }
 
+    /* ---------- The following are only used by TaskViewTouchHandler. ---------- */
+
+    @Override
+    public SingleAxisSwipeDetector.Direction getUpDownSwipeDirection() {
+        return HORIZONTAL;
+    }
+
+    @Override
+    public int getUpDirection(boolean isRtl) {
+        return isRtl ? SingleAxisSwipeDetector.DIRECTION_NEGATIVE
+                : SingleAxisSwipeDetector.DIRECTION_POSITIVE;
+    }
+
+    @Override
+    public boolean isGoingUp(float displacement, boolean isRtl) {
+        return isRtl ? displacement < 0 : displacement > 0;
+    }
+
+    @Override
+    public int getTaskDragDisplacementFactor(boolean isRtl) {
+        return isRtl ? 1 : -1;
+    }
+
+    /* -------------------- */
+
     @Override
     public ChildBounds getChildBounds(View child, int childStart, int pageCenter,
         boolean layoutChild) {