Fix mouse wheel over-scrolls when display is scaled and scroll is paginated

ui/events/blink/blink_event_util_unittest.cc

Index: ui/events/blink/blink_event_util_unittest.cc
diff --git a/ui/events/blink/blink_event_util_unittest.cc b/ui/events/blink/blink_event_util_unittest.cc
index 1bee59157f5832fa87e92ad83c5ee0bbe761ba49..260f63682f5b71207f0cf759307bf7d4a9752ea5 100644
--- a/ui/events/blink/blink_event_util_unittest.cc
+++ b/ui/events/blink/blink_event_util_unittest.cc
@@ -8,6 +8,7 @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebGestureEvent.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
+#include "third_party/WebKit/public/platform/WebMouseWheelEvent.h"
 #include "ui/events/gesture_event_details.h"
 
 namespace ui {
@@ -28,6 +29,108 @@ TEST(BlinkEventUtilTest, NoScalingWith1DSF) {
   EXPECT_TRUE(ScaleWebInputEvent(event, 2.f));
 }
 
+TEST(BlinkEventUtilTest, NonPaginatedWebMouseWheelEvent) {
+  blink::WebMouseWheelEvent event(blink::WebInputEvent::MouseWheel,
+                                  blink::WebInputEvent::NoModifiers,
+                                  blink::WebInputEvent::TimeStampForTesting);
+  event.deltaX = 1.f;
+  event.deltaY = 1.f;
+  event.wheelTicksX = 1.f;
+  event.wheelTicksY = 1.f;
+  event.scrollByPage = false;
+  std::unique_ptr<blink::WebInputEvent> webEvent =
+      ScaleWebInputEvent(event, 2.f);
+  EXPECT_TRUE(webEvent);
+  blink::WebMouseWheelEvent* mouseWheelEvent =
+      static_cast<blink::WebMouseWheelEvent*>(webEvent.get());
+  EXPECT_EQ(2.f, mouseWheelEvent->deltaX);
+  EXPECT_EQ(2.f, mouseWheelEvent->deltaY);
+  EXPECT_EQ(2.f, mouseWheelEvent->wheelTicksX);
+  EXPECT_EQ(2.f, mouseWheelEvent->wheelTicksY);
+}
+
+TEST(BlinkEventUtilTest, PaginatedWebMouseWheelEvent) {
+  blink::WebMouseWheelEvent event(blink::WebInputEvent::MouseWheel,
+                                  blink::WebInputEvent::NoModifiers,
+                                  blink::WebInputEvent::TimeStampForTesting);
+  event.deltaX = 1.f;
+  event.deltaY = 1.f;
+  event.wheelTicksX = 1.f;
+  event.wheelTicksY = 1.f;
+  event.scrollByPage = true;
+  std::unique_ptr<blink::WebInputEvent> webEvent =
+      ScaleWebInputEvent(event, 2.f);
+  EXPECT_TRUE(webEvent);
+  blink::WebMouseWheelEvent* mouseWheelEvent =
+      static_cast<blink::WebMouseWheelEvent*>(webEvent.get());
+  EXPECT_EQ(1.f, mouseWheelEvent->deltaX);
+  EXPECT_EQ(1.f, mouseWheelEvent->deltaY);
+  EXPECT_EQ(1.f, mouseWheelEvent->wheelTicksX);
+  EXPECT_EQ(1.f, mouseWheelEvent->wheelTicksY);
+}
+
+TEST(BlinkEventUtilTest, NonPaginatedScrollBeginEvent) {
+  ui::GestureEventDetails details(ui::ET_GESTURE_SCROLL_BEGIN, 1, 1);
+  details.set_device_type(ui::GestureDeviceType::DEVICE_TOUCHSCREEN);
+  auto event =
+      CreateWebGestureEvent(details, base::TimeTicks(), gfx::PointF(1.f, 1.f),
+                            gfx::PointF(1.f, 1.f), 0, 0U);
+  std::unique_ptr<blink::WebInputEvent> webEvent =
+      ScaleWebInputEvent(event, 2.f);
+  EXPECT_TRUE(webEvent);
+  blink::WebGestureEvent* gestureEvent =
+      static_cast<blink::WebGestureEvent*>(webEvent.get());
+  EXPECT_EQ(2.f, gestureEvent->data.scrollBegin.deltaXHint);
+  EXPECT_EQ(2.f, gestureEvent->data.scrollBegin.deltaYHint);
+}
+
+TEST(BlinkEventUtilTest, PaginatedScrollBeginEvent) {
+  ui::GestureEventDetails details(ui::ET_GESTURE_SCROLL_BEGIN, 1, 1,
+                                  ui::GestureEventDetails::ScrollUnits::PAGE);
+  details.set_device_type(ui::GestureDeviceType::DEVICE_TOUCHSCREEN);
+  auto event =
+      CreateWebGestureEvent(details, base::TimeTicks(), gfx::PointF(1.f, 1.f),
+                            gfx::PointF(1.f, 1.f), 0, 0U);
+  std::unique_ptr<blink::WebInputEvent> webEvent =
+      ScaleWebInputEvent(event, 2.f);
+  EXPECT_TRUE(webEvent);
+  blink::WebGestureEvent* gestureEvent =
+      static_cast<blink::WebGestureEvent*>(webEvent.get());
+  EXPECT_EQ(1.f, gestureEvent->data.scrollBegin.deltaXHint);
+  EXPECT_EQ(1.f, gestureEvent->data.scrollBegin.deltaYHint);
+}
+
+TEST(BlinkEventUtilTest, NonPaginatedScrollUpdateEvent) {
+  ui::GestureEventDetails details(ui::ET_GESTURE_SCROLL_UPDATE, 1, 1);
+  details.set_device_type(ui::GestureDeviceType::DEVICE_TOUCHSCREEN);
+  auto event =
+      CreateWebGestureEvent(details, base::TimeTicks(), gfx::PointF(1.f, 1.f),
+                            gfx::PointF(1.f, 1.f), 0, 0U);
+  std::unique_ptr<blink::WebInputEvent> webEvent =
+      ScaleWebInputEvent(event, 2.f);
+  EXPECT_TRUE(webEvent);
+  blink::WebGestureEvent* gestureEvent =
+      static_cast<blink::WebGestureEvent*>(webEvent.get());
+  EXPECT_EQ(2.f, gestureEvent->data.scrollUpdate.deltaX);
+  EXPECT_EQ(2.f, gestureEvent->data.scrollUpdate.deltaY);
+}
+
+TEST(BlinkEventUtilTest, PaginatedScrollUpdateEvent) {
+  ui::GestureEventDetails details(ui::ET_GESTURE_SCROLL_UPDATE, 1, 1,
+                                  ui::GestureEventDetails::ScrollUnits::PAGE);
+  details.set_device_type(ui::GestureDeviceType::DEVICE_TOUCHSCREEN);
+  auto event =
+      CreateWebGestureEvent(details, base::TimeTicks(), gfx::PointF(1.f, 1.f),
+                            gfx::PointF(1.f, 1.f), 0, 0U);
+  std::unique_ptr<blink::WebInputEvent> webEvent =
+      ScaleWebInputEvent(event, 2.f);
+  EXPECT_TRUE(webEvent);
+  blink::WebGestureEvent* gestureEvent =
+      static_cast<blink::WebGestureEvent*>(webEvent.get());
+  EXPECT_EQ(1.f, gestureEvent->data.scrollUpdate.deltaX);
+  EXPECT_EQ(1.f, gestureEvent->data.scrollUpdate.deltaY);
+}
+
 TEST(BlinkEventUtilTest, TouchEventCoalescing) {
   blink::WebTouchPoint touch_point;
   touch_point.id = 1;