Implement Wheel Gesture Scrolling on OSX.

content/browser/renderer_host/input/mouse_wheel_event_queue_unittest.cc

Index: content/browser/renderer_host/input/mouse_wheel_event_queue_unittest.cc
diff --git a/content/browser/renderer_host/input/mouse_wheel_event_queue_unittest.cc b/content/browser/renderer_host/input/mouse_wheel_event_queue_unittest.cc
index f9e10a901301818fb9270dc1fc3056c222353374..6ff9061bb3d0238f03ab93ae8ba06acf38c385eb 100644
--- a/content/browser/renderer_host/input/mouse_wheel_event_queue_unittest.cc
+++ b/content/browser/renderer_host/input/mouse_wheel_event_queue_unittest.cc
@@ -34,6 +34,95 @@ base::TimeDelta DefaultScrollEndTimeoutDelay() {
   return base::TimeDelta::FromMilliseconds(kScrollEndTimeoutMs);
 }
 
+struct CombinedEvent {

[tdresser, 2016/03/09 14:30:06]

What about just storing a WebInputEvent?
You'd need a few extra casts, but it might be cleaner.

[dtapuska, 2016/03/09 16:12:29]

Done.

+ public:
+  explicit CombinedEvent(const WebGestureEvent& event) { data.gesture = event; }
+  explicit CombinedEvent(const WebMouseWheelEvent& event) {
+    data.mouse_wheel = event;
+  }
+  union Data {
+    WebGestureEvent gesture;
+    WebMouseWheelEvent mouse_wheel;
+
+    Data() { memset(this, 0, sizeof(Data)); }
+  } data;
+};
+
+#define EXPECT_GESTURE_SCROLL_BEGIN_IMPL(event)                          \
+  EXPECT_EQ(WebInputEvent::GestureScrollBegin, event.data.gesture.type); \
+  EXPECT_EQ(kWheelScrollX, event.data.gesture.x);                        \
+  EXPECT_EQ(kWheelScrollY, event.data.gesture.y);                        \
+  EXPECT_EQ(kWheelScrollGlobalX, event.data.gesture.globalX);            \
+  EXPECT_EQ(kWheelScrollGlobalY, event.data.gesture.globalY);            \
+  EXPECT_EQ(scroll_units, event.data.gesture.data.scrollBegin.deltaHintUnits);
+
+#define EXPECT_GESTURE_SCROLL_BEGIN(event)                     \
+  EXPECT_GESTURE_SCROLL_BEGIN_IMPL(event);                     \
+  EXPECT_FALSE(event.data.gesture.data.scrollBegin.synthetic); \
+  EXPECT_FALSE(event.data.gesture.data.scrollBegin.inertial);
+
+#define EXPECT_SYNTHETIC_GESTURE_SCROLL_BEGIN(event)          \
+  EXPECT_GESTURE_SCROLL_BEGIN_IMPL(event);                    \
+  EXPECT_TRUE(event.data.gesture.data.scrollBegin.synthetic); \
+  EXPECT_FALSE(event.data.gesture.data.scrollBegin.inertial);
+
+#define EXPECT_INERTIAL_GESTURE_SCROLL_BEGIN(event)            \
+  EXPECT_GESTURE_SCROLL_BEGIN_IMPL(event);                     \
+  EXPECT_FALSE(event.data.gesture.data.scrollBegin.synthetic); \
+  EXPECT_TRUE(event.data.gesture.data.scrollBegin.inertial);
+
+#define EXPECT_SYNTHETIC_INERTIAL_GESTURE_SCROLL_BEGIN(event) \
+  EXPECT_GESTURE_SCROLL_BEGIN_IMPL(event);                    \
+  EXPECT_TRUE(event.data.gesture.data.scrollBegin.synthetic); \
+  EXPECT_TRUE(event.data.gesture.data.scrollBegin.inertial);
+
+#define EXPECT_GESTURE_SCROLL_UPDATE_IMPL(event)                            \
+  EXPECT_EQ(WebInputEvent::GestureScrollUpdate, event.data.gesture.type);   \
+  EXPECT_EQ(scroll_units, event.data.gesture.data.scrollUpdate.deltaUnits); \
+  EXPECT_EQ(kWheelScrollX, event.data.gesture.x);                           \
+  EXPECT_EQ(kWheelScrollY, event.data.gesture.y);                           \
+  EXPECT_EQ(kWheelScrollGlobalX, event.data.gesture.globalX);               \
+  EXPECT_EQ(kWheelScrollGlobalY, event.data.gesture.globalY);
+
+#define EXPECT_GESTURE_SCROLL_UPDATE(event) \
+  EXPECT_GESTURE_SCROLL_UPDATE_IMPL(event); \
+  EXPECT_FALSE(event.data.gesture.data.scrollUpdate.inertial);
+
+#define EXPECT_INERTIAL_GESTURE_SCROLL_UPDATE(event) \
+  EXPECT_GESTURE_SCROLL_UPDATE_IMPL(event);          \
+  EXPECT_TRUE(event.data.gesture.data.scrollUpdate.inertial);
+
+#define EXPECT_GESTURE_SCROLL_END_IMPL(event)                            \
+  EXPECT_EQ(WebInputEvent::GestureScrollEnd, event.data.gesture.type);   \
+  EXPECT_EQ(scroll_units, event.data.gesture.data.scrollEnd.deltaUnits); \
+  EXPECT_EQ(kWheelScrollX, event.data.gesture.x);                        \
+  EXPECT_EQ(kWheelScrollY, event.data.gesture.y);                        \
+  EXPECT_EQ(kWheelScrollGlobalX, event.data.gesture.globalX);            \
+  EXPECT_EQ(kWheelScrollGlobalY, event.data.gesture.globalY);
+
+#define EXPECT_GESTURE_SCROLL_END(event)                     \
+  EXPECT_GESTURE_SCROLL_END_IMPL(event);                     \
+  EXPECT_FALSE(event.data.gesture.data.scrollEnd.synthetic); \
+  EXPECT_FALSE(event.data.gesture.data.scrollEnd.inertial);
+
+#define EXPECT_SYNTHETIC_GESTURE_SCROLL_END(event)          \
+  EXPECT_GESTURE_SCROLL_END_IMPL(event);                    \
+  EXPECT_TRUE(event.data.gesture.data.scrollEnd.synthetic); \
+  EXPECT_FALSE(event.data.gesture.data.scrollEnd.inertial);
+
+#define EXPECT_INERTIAL_GESTURE_SCROLL_END(event)            \
+  EXPECT_GESTURE_SCROLL_END_IMPL(event);                     \
+  EXPECT_FALSE(event.data.gesture.data.scrollEnd.synthetic); \
+  EXPECT_TRUE(event.data.gesture.data.scrollEnd.inertial);
+
+#define EXPECT_SYNTHETIC_INERTIAL_GESTURE_SCROLL_END(event) \
+  EXPECT_GESTURE_SCROLL_END_IMPL(event);                    \
+  EXPECT_TRUE(event.data.gesture.data.scrollEnd.synthetic); \
+  EXPECT_TRUE(event.data.gesture.data.scrollEnd.inertial);
+
+#define EXPECT_MOUSE_WHEEL(event) \
+  EXPECT_EQ(WebInputEvent::MouseWheel, event.data.mouse_wheel.type);
+
 }  // namespace
 
 class MouseWheelEventQueueTest : public testing::Test,
@@ -50,12 +139,11 @@ class MouseWheelEventQueueTest : public testing::Test,
   // MouseWheelEventQueueClient
   void SendMouseWheelEventImmediately(
       const MouseWheelEventWithLatencyInfo& event) override {
-    sent_events_.push_back(event.event);
+    sent_events_.push_back(CombinedEvent(event.event));
   }
 
   void SendGestureEvent(const GestureEventWithLatencyInfo& event) override {
-    sent_events_.push_back(event.event);
-    sent_gesture_events_.push_back(event.event);
+    sent_events_.push_back(CombinedEvent(event.event));
   }
 
   void OnMouseWheelEventAck(const MouseWheelEventWithLatencyInfo& event,
@@ -75,18 +163,13 @@ class MouseWheelEventQueueTest : public testing::Test,
 
   bool event_in_flight() const { return queue_->event_in_flight(); }
 
-  std::vector<WebInputEvent>& all_sent_events() { return sent_events_; }
-
-  std::vector<WebGestureEvent>& sent_gesture_events() {
-    return sent_gesture_events_;
-  }
+  std::vector<CombinedEvent>& all_sent_events() { return sent_events_; }
 
   const WebMouseWheelEvent& acked_event() const { return last_acked_event_; }
 
   size_t GetAndResetSentEventCount() {
     size_t count = sent_events_.size();
     sent_events_.clear();
-    sent_gesture_events_.clear();
     return count;
   }
 
@@ -113,6 +196,24 @@ class MouseWheelEventQueueTest : public testing::Test,
             x, y, global_x, global_y, dX, dY, modifiers, high_precision)));
   }
 
+  void SendMouseWheelWithPhase(
+      float x,
+      float y,
+      float global_x,
+      float global_y,
+      float dX,
+      float dY,
+      int modifiers,
+      bool high_precision,
+      blink::WebMouseWheelEvent::Phase phase,
+      blink::WebMouseWheelEvent::Phase momentum_phase) {
+    WebMouseWheelEvent event = SyntheticWebMouseWheelEventBuilder::Build(
+        x, y, global_x, global_y, dX, dY, modifiers, high_precision);
+    event.phase = phase;
+    event.momentumPhase = momentum_phase;
+    queue_->QueueEvent(MouseWheelEventWithLatencyInfo(event));
+  }
+
   void SendGestureEvent(WebInputEvent::Type type) {
     WebGestureEvent event;
     event.type = type;
@@ -152,36 +253,109 @@ class MouseWheelEventQueueTest : public testing::Test,
     EXPECT_EQ(WebInputEvent::MouseWheel, acked_event().type);
     EXPECT_EQ(1U, GetAndResetAckedEventCount());
     EXPECT_EQ(3U, all_sent_events().size());
-    EXPECT_EQ(WebInputEvent::GestureScrollBegin, all_sent_events()[0].type);
-    EXPECT_EQ(scroll_units,
-              sent_gesture_events()[0].data.scrollBegin.deltaHintUnits);
-    EXPECT_EQ(kWheelScrollX, sent_gesture_events()[0].x);
-    EXPECT_EQ(kWheelScrollY, sent_gesture_events()[0].y);
-    EXPECT_EQ(kWheelScrollGlobalX, sent_gesture_events()[0].globalX);
-    EXPECT_EQ(kWheelScrollGlobalY, sent_gesture_events()[0].globalY);
-    EXPECT_EQ(WebInputEvent::GestureScrollUpdate, all_sent_events()[1].type);
-    EXPECT_EQ(scroll_units,
-              sent_gesture_events()[1].data.scrollUpdate.deltaUnits);
-    EXPECT_EQ(kWheelScrollX, sent_gesture_events()[1].x);
-    EXPECT_EQ(kWheelScrollY, sent_gesture_events()[1].y);
-    EXPECT_EQ(kWheelScrollGlobalX, sent_gesture_events()[1].globalX);
-    EXPECT_EQ(kWheelScrollGlobalY, sent_gesture_events()[1].globalY);
-    EXPECT_EQ(WebInputEvent::MouseWheel, all_sent_events()[2].type);
+    EXPECT_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
+    EXPECT_MOUSE_WHEEL(all_sent_events()[2]);
     EXPECT_EQ(3U, GetAndResetSentEventCount());
 
     RunTasksAndWait(DefaultScrollEndTimeoutDelay() * 2);
     EXPECT_EQ(1U, all_sent_events().size());
-    EXPECT_EQ(WebInputEvent::GestureScrollEnd, all_sent_events()[0].type);
-    EXPECT_EQ(scroll_units, sent_gesture_events()[0].data.scrollEnd.deltaUnits);
-    EXPECT_EQ(kWheelScrollX, sent_gesture_events()[0].x);
-    EXPECT_EQ(kWheelScrollY, sent_gesture_events()[0].y);
-    EXPECT_EQ(kWheelScrollGlobalX, sent_gesture_events()[0].globalX);
-    EXPECT_EQ(kWheelScrollGlobalY, sent_gesture_events()[0].globalY);
+    EXPECT_GESTURE_SCROLL_END(all_sent_events()[0]);
+  }
+
+  void PhaseGestureSendingTest(bool high_precision) {
+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 1, 1, 0, high_precision,
+                            WebMouseWheelEvent::PhaseBegan,
+                            WebMouseWheelEvent::PhaseNone);

[tdresser, 2016/03/09 14:30:06]

I still find this difficult to read, as the expected result is so far from where
we dispatch the wheel event.

That being said, the approach you've taken with the EXPECT_* macros is a nice
cleanup.

Let's discuss this in person.

[dtapuska, 2016/03/09 16:12:29]

Done.

+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 5, 5, 0, high_precision,
+                            WebMouseWheelEvent::PhaseChanged,
+                            WebMouseWheelEvent::PhaseNone);
+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 0, 0, 0, high_precision,
+                            WebMouseWheelEvent::PhaseEnded,
+                            WebMouseWheelEvent::PhaseNone);
+    // Send a double phase end; OSX does it consistently; note the modifiers
+    // are set differently as to avoid coalescing.
+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 0, 0, 1, high_precision,
+                            WebMouseWheelEvent::PhaseEnded,
+                            WebMouseWheelEvent::PhaseNone);
+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 5, 5, 0, high_precision,
+                            WebMouseWheelEvent::PhaseNone,
+                            WebMouseWheelEvent::PhaseBegan);
+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 5, 5, 0, high_precision,
+                            WebMouseWheelEvent::PhaseNone,
+                            WebMouseWheelEvent::PhaseChanged);
+    SendMouseWheelWithPhase(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
+                            kWheelScrollGlobalY, 0, 0, 0, high_precision,
+                            WebMouseWheelEvent::PhaseNone,
+                            WebMouseWheelEvent::PhaseEnded);
+
+    EXPECT_EQ(6U, queued_event_count());
+    EXPECT_TRUE(event_in_flight());
+    EXPECT_EQ(1U, GetAndResetSentEventCount());
+
+    const WebGestureEvent::ScrollUnits scroll_units =
+        high_precision ? WebGestureEvent::PrecisePixels
+                       : WebGestureEvent::Pixels;
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(4U, all_sent_events().size());
+    EXPECT_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
+    EXPECT_SYNTHETIC_GESTURE_SCROLL_END(all_sent_events()[2]);
+    EXPECT_MOUSE_WHEEL(all_sent_events()[3]);
+    EXPECT_EQ(4U, GetAndResetSentEventCount());
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(4U, all_sent_events().size());
+    EXPECT_SYNTHETIC_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
+    EXPECT_SYNTHETIC_GESTURE_SCROLL_END(all_sent_events()[2]);
+    EXPECT_MOUSE_WHEEL(all_sent_events()[3]);
+    EXPECT_EQ(4U, GetAndResetSentEventCount());
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(3U, all_sent_events().size());
+    EXPECT_SYNTHETIC_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_GESTURE_SCROLL_END(all_sent_events()[1]);
+    EXPECT_MOUSE_WHEEL(all_sent_events()[2]);
+    EXPECT_EQ(3U, GetAndResetSentEventCount());
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(1U, all_sent_events().size());
+    EXPECT_MOUSE_WHEEL(all_sent_events()[0]);
+    EXPECT_EQ(1U, GetAndResetSentEventCount());
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(4U, all_sent_events().size());
+    EXPECT_INERTIAL_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_INERTIAL_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
+    EXPECT_SYNTHETIC_INERTIAL_GESTURE_SCROLL_END(all_sent_events()[2]);
+    EXPECT_MOUSE_WHEEL(all_sent_events()[3]);
+    EXPECT_EQ(4U, GetAndResetSentEventCount());
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(4U, all_sent_events().size());
+    EXPECT_SYNTHETIC_INERTIAL_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_INERTIAL_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
+    EXPECT_SYNTHETIC_INERTIAL_GESTURE_SCROLL_END(all_sent_events()[2]);
+    EXPECT_MOUSE_WHEEL(all_sent_events()[3]);
+    EXPECT_EQ(4U, GetAndResetSentEventCount());
+
+    SendMouseWheelEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+    EXPECT_EQ(2U, all_sent_events().size());
+    EXPECT_SYNTHETIC_INERTIAL_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+    EXPECT_INERTIAL_GESTURE_SCROLL_END(all_sent_events()[1]);
+    EXPECT_EQ(2U, GetAndResetSentEventCount());
   }
 
   scoped_ptr<MouseWheelEventQueue> queue_;
-  std::vector<WebInputEvent> sent_events_;
-  std::vector<WebGestureEvent> sent_gesture_events_;
+  std::vector<CombinedEvent> sent_events_;
   size_t acked_event_count_;
   InputEventAckState last_acked_event_state_;
   base::MessageLoopForUI message_loop_;
@@ -230,8 +404,21 @@ TEST_F(MouseWheelEventQueueTest, GestureSendingPrecisePixels) {
   GestureSendingTest(false);
 }
 
+TEST_F(MouseWheelEventQueueTest, GestureSendingWithPhaseInformation) {
+  SetUpForGestureTesting(true);
+  PhaseGestureSendingTest(false);
+}
+
+TEST_F(MouseWheelEventQueueTest,
+       GestureSendingWithPhaseInformationPrecisePixels) {
+  SetUpForGestureTesting(true);
+  PhaseGestureSendingTest(true);
+}
+
 TEST_F(MouseWheelEventQueueTest, GestureSendingInterrupted) {
   SetUpForGestureTesting(true);
+  const WebGestureEvent::ScrollUnits scroll_units = WebGestureEvent::Pixels;
+
   SendMouseWheel(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
                  kWheelScrollGlobalY, 1, 1, 0, false);
   EXPECT_EQ(0U, queued_event_count());
@@ -245,14 +432,14 @@ TEST_F(MouseWheelEventQueueTest, GestureSendingInterrupted) {
   EXPECT_EQ(WebInputEvent::MouseWheel, acked_event().type);
   EXPECT_EQ(1U, GetAndResetAckedEventCount());
   EXPECT_EQ(2U, all_sent_events().size());
-  EXPECT_EQ(WebInputEvent::GestureScrollBegin, all_sent_events()[0].type);
-  EXPECT_EQ(WebInputEvent::GestureScrollUpdate, all_sent_events()[1].type);
+  EXPECT_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+  EXPECT_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
   EXPECT_EQ(2U, GetAndResetSentEventCount());
 
   // Ensure that a gesture scroll begin terminates the current scroll event.
   SendGestureEvent(WebInputEvent::GestureScrollBegin);
   EXPECT_EQ(1U, all_sent_events().size());
-  EXPECT_EQ(WebInputEvent::GestureScrollEnd, all_sent_events()[0].type);
+  EXPECT_GESTURE_SCROLL_END(all_sent_events()[0]);
   EXPECT_EQ(1U, GetAndResetSentEventCount());
 
   SendMouseWheel(kWheelScrollX, kWheelScrollY, kWheelScrollGlobalX,
@@ -286,8 +473,8 @@ TEST_F(MouseWheelEventQueueTest, GestureSendingInterrupted) {
   EXPECT_EQ(WebInputEvent::MouseWheel, acked_event().type);
   EXPECT_EQ(1U, GetAndResetAckedEventCount());
   EXPECT_EQ(2U, all_sent_events().size());
-  EXPECT_EQ(WebInputEvent::GestureScrollBegin, all_sent_events()[0].type);
-  EXPECT_EQ(WebInputEvent::GestureScrollUpdate, all_sent_events()[1].type);
+  EXPECT_GESTURE_SCROLL_BEGIN(all_sent_events()[0]);
+  EXPECT_GESTURE_SCROLL_UPDATE(all_sent_events()[1]);
   EXPECT_EQ(2U, GetAndResetSentEventCount());
 }