Virtual Desks and Overview swipes finger count changes

- Tab scrubbing: change to use 4-finger gestures.
- Desk switch: change to use 3-finger  gestures.
- Overview selection: change to use 4-finger gestures.

BUG=995911
TEST=Manually, modify existing tests.

Change-Id: I867f3c0033647cc15998e6ef3bce02ac43c2ae7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1764832Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689540}

ash/wm/gestures/wm_gesture_handler.cc

@@ -14,6 +14,49 @@
 
 namespace ash {
 
+namespace {
+
+// Handles vertical 3-finger scroll gesture by entering overview on scrolling
+// up, and exiting it on scrolling down.
+// Returns true if the gesture was handled.
+bool Handle3FingerVerticalScroll(float scroll_y) {
+  auto* overview_controller = Shell::Get()->overview_controller();
+  const bool in_overview = overview_controller->InOverviewSession();
+  if (in_overview) {
+    if (scroll_y < WmGestureHandler::kVerticalThresholdDp)
+      return false;
+
+    base::RecordAction(base::UserMetricsAction("Touchpad_Gesture_Overview"));
+    if (overview_controller->AcceptSelection())
+      return true;
+    overview_controller->EndOverview();
+  } else {
+    if (scroll_y > -WmGestureHandler::kVerticalThresholdDp)
+      return false;
+
+    base::RecordAction(base::UserMetricsAction("Touchpad_Gesture_Overview"));
+    overview_controller->StartOverview();
+  }
+
+  return true;
+}
+
+// Handles horizontal 3-finger scroll by switching desks if possible.
+// Returns true if the gesture was handled.
+bool Handle3FingerHorizontalScroll(float scroll_x) {
+  if (std::fabs(scroll_x) < WmGestureHandler::kHorizontalThresholdDp)
+    return false;
+
+  // This does not invert if the user changes their touchpad settings
+  // currently. The scroll works Australian way (scroll left to go to the
+  // desk on the right and vice versa).
+  DesksController::Get()->ActivateAdjacentDesk(
+      /*going_left=*/scroll_x > 0, DesksSwitchSource::kDeskSwitchTouchpad);
+  return true;
+}
+
+}  // namespace
+
 WmGestureHandler::WmGestureHandler() = default;
 
 WmGestureHandler::~WmGestureHandler() = default;
@@ -70,56 +113,22 @@ bool WmGestureHandler::EndScroll() {
   if (finger_count == 0)
     return false;
 
-  // Horizontal 4-finger scroll switches desks if possible.
-  if (finger_count == 4) {
+  if (finger_count == 3) {
     if (std::fabs(scroll_x) < std::fabs(scroll_y))
-      return false;
-
-    if (std::fabs(scroll_x) < kHorizontalThresholdDp)
-      return false;
+      return Handle3FingerVerticalScroll(scroll_y);
 
-    // This does not invert if the user changes their touchpad settings
-    // currently. The scroll works Australian way (scroll left to go to the
-    // desk on the right and vice versa).
-    DesksController::Get()->ActivateAdjacentDesk(
-        /*going_left=*/scroll_x > 0, DesksSwitchSource::kDeskSwitchTouchpad);
-    return true;
+    return Handle3FingerHorizontalScroll(scroll_x);
   }
 
-  DCHECK_EQ(3, finger_count);
-  // Horizontal 3-finger scroll moves selection when already in overview mode.
-  if (MoveOverviewSelection(finger_count, scroll_x, scroll_y))
-    return true;
-
-  if (std::fabs(scroll_x) >= std::fabs(scroll_y))
-    return false;
-
-  auto* overview_controller = Shell::Get()->overview_controller();
-  const bool in_overview = overview_controller->InOverviewSession();
-  // Use vertical 3-finger scroll gesture up to enter overview, down to exit.
-  if (in_overview) {
-    if (scroll_y < 0 || scroll_y < kVerticalThresholdDp)
-      return false;
-
-    base::RecordAction(base::UserMetricsAction("Touchpad_Gesture_Overview"));
-    if (overview_controller->AcceptSelection())
-      return true;
-    overview_controller->EndOverview();
-  } else {
-    if (scroll_y > 0 || scroll_y > -kVerticalThresholdDp)
-      return false;
-
-    base::RecordAction(base::UserMetricsAction("Touchpad_Gesture_Overview"));
-    overview_controller->StartOverview();
-  }
-
-  return true;
+  DCHECK_EQ(4, finger_count);
+  // Horizontal 4-finger scroll moves selection when already in overview mode.
+  return MoveOverviewSelection(finger_count, scroll_x, scroll_y);
 }
 
 bool WmGestureHandler::MoveOverviewSelection(int finger_count,
                                              float scroll_x,
                                              float scroll_y) {
-  if (finger_count != 3)
+  if (finger_count != 4)
     return false;
 
   auto* overview_controller = Shell::Get()->overview_controller();

ash/wm/gestures/wm_gesture_handler_unittest.cc

@@ -68,7 +68,7 @@ TEST_F(WmGestureHandlerTest, VerticalScrolls) {
   EXPECT_FALSE(InOverviewSession());
 }
 
-// Tests three finger horizontal scroll gesture to move selection left or right.
+// Tests four finger horizontal scroll gesture to move selection left or right.
 TEST_F(WmGestureHandlerTest, HorizontalScrollInOverview) {
   const gfx::Rect bounds(0, 0, 400, 400);
   std::unique_ptr<aura::Window> window1 = CreateTestWindow(bounds);
@@ -88,7 +88,7 @@ TEST_F(WmGestureHandlerTest, HorizontalScrollInOverview) {
   auto scroll_until_window_highlighted = [this](float x_offset,
                                                 float y_offset) {
     do {
-      Scroll(x_offset, y_offset, /*num_fingers=*/3);
+      Scroll(x_offset, y_offset, /*num_fingers=*/4);
     } while (!GetHighlightedWindow());
   };
 
@@ -99,15 +99,16 @@ TEST_F(WmGestureHandlerTest, HorizontalScrollInOverview) {
   scroll_until_window_highlighted(horizontal_scroll * 3, 0);
   EXPECT_TRUE(InOverviewSession());
 
-  // Short scroll left (3 fingers) moves selection to the third window.
+  // Short scroll left (4 fingers) moves selection to the third window.
   scroll_until_window_highlighted(-horizontal_scroll, 0);
   EXPECT_TRUE(InOverviewSession());
 
-  // Short scroll left (3 fingers) moves selection to the second window.
+  // Short scroll left (4 fingers) moves selection to the second window.
   scroll_until_window_highlighted(-horizontal_scroll, 0);
   EXPECT_TRUE(InOverviewSession());
 
-  // Swiping down exits and selects the currently-highlighted window.
+  // Swiping down (3 fingers) exits and selects the currently-highlighted
+  // window.
   Scroll(0, vertical_scroll, 3);
   EXPECT_FALSE(InOverviewSession());
 
@@ -166,7 +167,7 @@ class DesksGestureHandlerTest : public WmGestureHandlerTest {
     DeskSwitchAnimationWaiter waiter;
     const float x_offset =
         (scroll_left ? -1 : 1) * WmGestureHandler::kHorizontalThresholdDp;
-    Scroll(x_offset, 0, 4);
+    Scroll(x_offset, 0, 3);
     waiter.Wait();
   }
 
@@ -176,7 +177,7 @@ class DesksGestureHandlerTest : public WmGestureHandlerTest {
   DISALLOW_COPY_AND_ASSIGN(DesksGestureHandlerTest);
 };
 
-// Tests that a four-finger scroll will switch desks as expected.
+// Tests that a three-finger horizontal scroll will switch desks as expected.
 TEST_F(DesksGestureHandlerTest, HorizontalScrolls) {
   auto* desk_controller = DesksController::Get();
   desk_controller->NewDesk(DesksCreationRemovalSource::kButton);
@@ -194,7 +195,7 @@ TEST_F(DesksGestureHandlerTest, HorizontalScrolls) {
   // Tests that since there is no previous desk, we remain on the same desk when
   // scrolling right.
   const float long_scroll = WmGestureHandler::kHorizontalThresholdDp;
-  Scroll(long_scroll, 0.f, 4);
+  Scroll(long_scroll, 0.f, 3);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 }
 
@@ -209,16 +210,16 @@ 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, 4);
+  Scroll(short_scroll, 0.f, 3);
   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, 4);
+  Scroll(long_scroll, long_scroll + 10.f, 3);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 
   // Tests that a vertical scroll does not switch desks.
-  Scroll(0.f, WmGestureHandler::kVerticalThresholdDp, 4);
+  Scroll(0.f, WmGestureHandler::kVerticalThresholdDp, 3);
   EXPECT_EQ(desk_controller->desks()[0].get(), desk_controller->active_desk());
 }
 
@@ -233,7 +234,7 @@ TEST_F(DesksGestureHandlerTest, NoDoubleDeskChange) {
 
   const float long_scroll = WmGestureHandler::kHorizontalThresholdDp * 3;
   DeskSwitchAnimationWaiter waiter;
-  Scroll(-long_scroll, 0, 4);
+  Scroll(-long_scroll, 0, 3);
   waiter.Wait();
   EXPECT_EQ(desk_controller->desks()[1].get(), desk_controller->active_desk());
 }

chrome/browser/ui/ash/tab_scrubber.cc

@@ -94,7 +94,7 @@ void TabScrubber::OnScrollEvent(ui::ScrollEvent* event) {
     return;
   }
 
-  if (event->finger_count() != 3)
+  if (event->finger_count() != 4)
     return;
 
   Browser* browser = GetActiveBrowser();

chrome/browser/ui/ash/tab_scrubber.h

@@ -23,7 +23,7 @@ namespace gfx {
 class Point;
 }
 
-// Class to enable quick tab switching via horizontal 3 finger swipes.
+// Class to enable quick tab switching via horizontal 4 finger swipes.
 class TabScrubber : public ui::EventHandler,
                     public BrowserListObserver,
                     public TabStripObserver {

chrome/browser/ui/ash/tab_scrubber_browsertest.cc

@@ -152,7 +152,7 @@ class TabScrubberTest : public InProcessBrowserTest,
                  GetStartX(browser, active_index, direction);
     ui::ScrollEvent scroll_event(ui::ET_SCROLL, gfx::Point(0, 0),
                                  ui::EventTimeForNow(), 0, offset, 0, offset, 0,
-                                 3);
+                                 4);
     event_generator->Dispatch(&scroll_event);
   }
 
@@ -242,8 +242,8 @@ class TabScrubberTest : public InProcessBrowserTest,
   // forces the TabScrubber to complete any pending activation.
   class ScrollGenerator {
    public:
-    // TabScrubber reacts to three-finger scrolls.
-    static const int kNumFingers = 3;
+    // TabScrubber reacts to four-finger scrolls.
+    static const int kNumFingers = 4;
 
     explicit ScrollGenerator(ui::test::EventGenerator* event_generator)
         : event_generator_(event_generator) {