Flip the gesture direction of switching desks

The M87 changes the switching desk gesture direction when reverse
scrolling for touchpad is off. This CL flips gesture direction of
switching desks and show a toast when reverse scrolling is off.

Bug: 1107183
Change-Id: I58dc18331bc9f917a571b033b8caac63a3da95bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2444438
Commit-Queue: Xiaodan Zhu <zxdan@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813265}

ash/wm/gestures/wm_gesture_handler.cc

@@ -171,8 +171,8 @@ bool HandleDesksSwitchHorizontalScroll(float scroll_x) {
   if (std::fabs(scroll_x) < WmGestureHandler::kHorizontalThresholdDp)
     return false;
 
-  if (IsNaturalScrollOn()) {
-    if (GetOffset(scroll_x) < 0 && !DesksController::Get()->GetNextDesk() &&
+  if (!IsNaturalScrollOn()) {
+    if (scroll_x > 0 && !DesksController::Get()->GetNextDesk() &&
         DesksController::Get()->GetPreviousDesk()) {
       if (!gDidWrongLastDeskGesture) {
         gDidWrongLastDeskGesture = true;
@@ -180,7 +180,7 @@ bool HandleDesksSwitchHorizontalScroll(float scroll_x) {
         ShowReverseGestureToast(kSwitchLastDeskToastId,
                                 IDS_CHANGE_LAST_DESK_REVERSE_GESTURE);
       }
-    } else if (GetOffset(scroll_x) > 0 &&
+    } else if (scroll_x < 0 &&
                !DesksController::Get()->GetPreviousDesk() &&
                DesksController::Get()->GetNextDesk()) {
       if (!gDidWrongNextDeskGesture) {
@@ -197,9 +197,9 @@ bool HandleDesksSwitchHorizontalScroll(float scroll_x) {
     }
   }
 
-  // If touchpad reverse scroll is on, the swip direction will invert.
+  // If touchpad reverse scroll is on, the swipe direction will invert.
   return DesksController::Get()->ActivateAdjacentDesk(
-      /*going_left=*/GetOffset(scroll_x) > 0,
+      /*going_left=*/GetOffset(scroll_x) < 0,
       DesksSwitchSource::kDeskSwitchTouchpad);
 }
 

ash/wm/gestures/wm_gesture_handler_unittest.cc

@@ -246,18 +246,18 @@ TEST_F(DesksGestureHandlerTest, HorizontalScrolls) {
   ASSERT_EQ(2u, desk_controller->desks().size());
   ASSERT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 
-  // Tests that scrolling left should take us to the next desk.
-  ScrollToSwitchDesks(/*scroll_left=*/true);
+  // Tests that scrolling right should take us to the next desk.
+  ScrollToSwitchDesks(/*scroll_left=*/false);
   EXPECT_EQ(desk_controller->desks()[1].get(), desk_controller->active_desk());
 
-  // Tests that scrolling right should take us to the previous desk.
-  ScrollToSwitchDesks(/*scroll_left=*/false);
+  // Tests that scrolling left should take us to the previous desk.
+  ScrollToSwitchDesks(/*scroll_left=*/true);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 
   // Tests that since there is no previous desk, we remain on the same desk when
-  // scrolling right.
+  // scrolling left.
   const float long_scroll = WmGestureHandler::kHorizontalThresholdDp;
-  Scroll(long_scroll, 0.f, kNumFingersForDesksSwitch);
+  Scroll(-long_scroll, 0.f, kNumFingersForDesksSwitch);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 }
 
@@ -272,12 +272,12 @@ TEST_F(DesksGestureHandlerTest, NoDeskChanges) {
   const float short_scroll = WmGestureHandler::kHorizontalThresholdDp - 10.f;
   const float long_scroll = WmGestureHandler::kHorizontalThresholdDp;
   // Tests that a short horizontal scroll does not switch desks.
-  Scroll(short_scroll, 0.f, kNumFingersForDesksSwitch);
+  Scroll(-short_scroll, 0.f, kNumFingersForDesksSwitch);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 
   // Tests that a scroll that meets the horizontal requirements, but is mostly
   // vertical does not switch desks.
-  Scroll(long_scroll, long_scroll + 10.f, kNumFingersForDesksSwitch);
+  Scroll(-long_scroll, long_scroll + 10.f, kNumFingersForDesksSwitch);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 
   // Tests that a vertical scroll does not switch desks.
@@ -297,7 +297,7 @@ TEST_F(DesksGestureHandlerTest, NoDoubleDeskChange) {
 
   const float long_scroll = WmGestureHandler::kHorizontalThresholdDp * 3;
   DeskSwitchAnimationWaiter waiter;
-  Scroll(-long_scroll, 0, kNumFingersForDesksSwitch);
+  Scroll(long_scroll, 0, kNumFingersForDesksSwitch);
   waiter.Wait();
   EXPECT_EQ(desk_controller->desks()[1].get(), desk_controller->active_desk());
 }
@@ -317,7 +317,7 @@ TEST_F(DesksGestureHandlerTest, NoDeskChangesInLockScreen) {
   ASSERT_TRUE(session_controller->IsScreenLocked());
 
   const float long_scroll = WmGestureHandler::kHorizontalThresholdDp * 3;
-  Scroll(-long_scroll, 0, kNumFingersForDesksSwitch);
+  Scroll(long_scroll, 0, kNumFingersForDesksSwitch);
   EXPECT_FALSE(desk_controller->AreDesksBeingModified());
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 }
@@ -564,11 +564,11 @@ TEST_F(ReverseGestureHandlerTest, SwitchDesk) {
   const Desk* desk1 = GetActiveDesk();
   const Desk* desk2 = GetNextDesk();
 
-  // Scroll right to get next desk.
-  ScrollToSwitchDesks(/*scroll_left=*/false);
+  // Scroll left to get next desk.
+  ScrollToSwitchDesks(/*scroll_left=*/true);
   EXPECT_EQ(desk2, GetActiveDesk());
-  // Scroll left to get previous desk.
-  ScrollToSwitchDesks(/*scroll_right=*/true);
+  // Scroll right to get previous desk.
+  ScrollToSwitchDesks(/*scroll_right=*/false);
   EXPECT_EQ(desk1, GetActiveDesk());
 }