MacViews: Handle three-finger swipe gestures for navigation.

ui/views/view_unittest_mac.mm

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/views/view.h"
+
+#import <Cocoa/Cocoa.h>
+
+#import "base/mac/scoped_nsobject.h"
+#include "base/optional.h"
+#include "ui/events/gesture_event_details.h"
+#include "ui/views/test/widget_test.h"
+
+// We can't create NSEventTypeSwipe using normal means, and rely on duck typing
+// instead.
+@interface FakeSwipeEvent : NSEvent
+@property CGFloat deltaX;
+@property CGFloat deltaY;
+@property(assign) NSWindow* window;
+@property NSPoint locationInWindow;
+@property NSEventModifierFlags modifierFlags;
+@property NSTimeInterval timestamp;
+@end
+
+@implementation FakeSwipeEvent
+@synthesize deltaX;
+@synthesize deltaY;
+@synthesize window;
+@synthesize locationInWindow;
+@synthesize modifierFlags;
+@synthesize timestamp;
+
+- (NSEventType)type {
+  return NSEventTypeSwipe;
+}
+
+- (NSEventSubtype)subtype {
+  // themblsha: In my testing, all native three-finger NSEventTypeSwipe events
+  // all had 0 as their subtype.
+  return static_cast<NSEventSubtype>(0);
+}
+@end
+
+namespace views {
+
+namespace {
+
+// Stores last received swipe gesture direction vector in
+// |last_swipe_gesture()|.
+class ThreeFingerSwipeView : public View {
+ public:
+  ThreeFingerSwipeView() {}
+
+  // View:
+  void OnGestureEvent(ui::GestureEvent* event) override {
+    EXPECT_EQ(ui::ET_GESTURE_SWIPE, event->details().type());
+
+    int dx = 0, dy = 0;
+    if (event->details().swipe_left())
+      dx = -1;
+
+    if (event->details().swipe_right()) {
+      EXPECT_EQ(0, dx);
+      dx = 1;
+    }
+
+    if (event->details().swipe_down())
+      dy = 1;
+
+    if (event->details().swipe_up()) {
+      EXPECT_EQ(0, dy);
+      dy = -1;
+    }
+
+    last_swipe_gesture_ = gfx::Point(dx, dy);
+  }
+
+  base::Optional<gfx::Point> last_swipe_gesture() const {
+    return last_swipe_gesture_;
+  }
+
+ private:
+  base::Optional<gfx::Point> last_swipe_gesture_;
+
+  DISALLOW_COPY_AND_ASSIGN(ThreeFingerSwipeView);
+};
+
+}  // namespace
+
+class ViewMacTest : public test::WidgetTest {
+ public:
+  ViewMacTest() {}
+
+  base::Optional<gfx::Point> SwipeGestureVector(int dx, int dy) {
+    base::scoped_nsobject<FakeSwipeEvent> swipe_event(
+        [[FakeSwipeEvent alloc] init]);
+    [swipe_event setDeltaX:dx];
+    [swipe_event setDeltaY:dy];
+    [swipe_event setWindow:widget_->GetNativeWindow()];
+    [swipe_event setLocationInWindow:NSMakePoint(50, 50)];
+    [swipe_event setTimestamp:[[NSProcessInfo processInfo] systemUptime]];
+
+    // BridgedContentView should create an appropriate ui::GestureEvent and pass
+    // it to the Widget.
+    [[widget_->GetNativeWindow() contentView] swipeWithEvent:swipe_event];
+    return view_->last_swipe_gesture();
+  }
+
+  // testing::Test:
+  void SetUp() override {
+    WidgetTest::SetUp();
+
+    widget_ = CreateTopLevelPlatformWidget();
+    widget_->SetBounds(gfx::Rect(0, 0, 100, 100));
+    widget_->Show();
+
+    view_ = new ThreeFingerSwipeView;
+    view_->SetSize(widget_->GetClientAreaBoundsInScreen().size());
+    widget_->GetContentsView()->AddChildView(view_);
+  }
+
+  void TearDown() override {
+    widget_->CloseNow();
+    WidgetTest::TearDown();
+  }
+
+ private:
+  Widget* widget_ = nullptr;
+  ThreeFingerSwipeView* view_ = nullptr;
+
+  DISALLOW_COPY_AND_ASSIGN(ViewMacTest);
+};
+
+// Three-finger swipes send immediate events and they cannot be tracked.
+TEST_F(ViewMacTest, HandlesThreeFingerSwipeGestures) {
+  // Note that positive delta is left and up for NSEvent, which is the inverse
+  // of ui::GestureEventDetails.
+  EXPECT_EQ(gfx::Point(1, 0), *SwipeGestureVector(-1, 0));
+  EXPECT_EQ(gfx::Point(-1, 0), *SwipeGestureVector(1, 0));
+  EXPECT_EQ(gfx::Point(0, 1), *SwipeGestureVector(0, -1));
+  EXPECT_EQ(gfx::Point(0, -1), *SwipeGestureVector(0, 1));
+}
+
+}  // namespace views