phase based wheel scroll latching for mac

content/browser/renderer_host/render_widget_host_view_mac_unittest.mm

Index: content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm b/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
index e482c755c8966ead410ed6881e340c63afa52a83..7bf0b1c5c8c63e93f77b9345c3ade86d98815f7a 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
@@ -16,7 +16,9 @@
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/histogram_tester.h"
+#include "base/test/scoped_feature_list.h"
 #include "base/test/simple_test_tick_clock.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/compositor/test/no_transport_image_transport_factory.h"
 #include "content/browser/frame_host/render_widget_host_view_guest.h"
@@ -28,6 +30,7 @@
 #include "content/common/view_messages.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_widget_host_view_mac_delegate.h"
+#include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_context.h"
@@ -52,6 +55,7 @@
 @interface MockPhaseMethods : NSObject {
 }
 
+- (NSEventPhase)phaseNone;
 - (NSEventPhase)phaseBegan;
 - (NSEventPhase)phaseChanged;
 - (NSEventPhase)phaseEnded;
@@ -59,6 +63,9 @@
 
 @implementation MockPhaseMethods
 
+- (NSEventPhase)phaseNone {
+  return NSEventPhaseNone;
+}
 - (NSEventPhase)phaseBegan {
   return NSEventPhaseBegan;
 }
@@ -297,6 +304,23 @@ NSEvent* MockScrollWheelEventWithPhase(SEL mockPhaseSelector, int32_t delta) {
   return event;
 }
 
+NSEvent* MockScrollWheelEventWithMomentumPhase(SEL mockPhaseSelector,
+                                               int32_t delta) {
+  // Create a dummy event with phaseNone. This is for resetting the phase info
+  // of CGEventRef.
+  MockScrollWheelEventWithPhase(@selector(phaseNone), 0);
+  CGEventRef cg_event = CGEventCreateScrollWheelEvent(
+      nullptr, kCGScrollEventUnitLine, 1, delta, 0);
+  CGEventTimestamp timestamp = 0;
+  CGEventSetTimestamp(cg_event, timestamp);
+  NSEvent* event = [NSEvent eventWithCGEvent:cg_event];
+  CFRelease(cg_event);
+  method_setImplementation(
+      class_getInstanceMethod([NSEvent class], @selector(momentumPhase)),
+      [MockPhaseMethods instanceMethodForSelector:mockPhaseSelector]);
+  return event;
+}
+
 }  // namespace
 
 class RenderWidgetHostViewMacTest : public RenderViewHostImplTestHarness {
@@ -1308,6 +1332,180 @@ TEST_F(RenderWidgetHostViewMacTest, Background) {
   host->ShutdownAndDestroyWidget(true);
 }
 
+class RenderWidgetHostViewMacWithWheelScrollLatchingEnabledTest
+    : public RenderWidgetHostViewMacTest {
+ public:
+  RenderWidgetHostViewMacWithWheelScrollLatchingEnabledTest() {
+    feature_list_.InitFromCommandLine(
+        features::kTouchpadAndWheelScrollLatching.name, "");
+  }
+
+ private:
+  base::test::ScopedFeatureList feature_list_;
+};
+
+// When wheel scroll latching is enabled, wheel end events are not sent
+// immediately, instead we start a timer to see if momentum phase of the scroll
+// starts or not.
+TEST_F(RenderWidgetHostViewMacWithWheelScrollLatchingEnabledTest,
+       WheelWithPhaseEndedIsNotForwardedImmediately) {
+  // Initialize the view associated with a MockRenderWidgetHostImpl, rather than
+  // the MockRenderProcessHost that is set up by the test harness which mocks
+  // out |OnMessageReceived()|.
+  TestBrowserContext browser_context;
+  MockRenderProcessHost* process_host =
+      new MockRenderProcessHost(&browser_context);
+  process_host->Init();
+  MockRenderWidgetHostDelegate delegate;
+  int32_t routing_id = process_host->GetNextRoutingID();
+  MockRenderWidgetHostImpl* host =
+      new MockRenderWidgetHostImpl(&delegate, process_host, routing_id);
+  RenderWidgetHostViewMac* view = new RenderWidgetHostViewMac(host, false);
+  process_host->sink().ClearMessages();
+
+  // Send an initial wheel event for scrolling by 3 lines.
+  NSEvent* wheelEvent1 =
+      MockScrollWheelEventWithPhase(@selector(phaseBegan), 3);
+  [view->cocoa_view() scrollWheel:wheelEvent1];
+  ASSERT_EQ(1U, process_host->sink().message_count());
+  process_host->sink().ClearMessages();
+
+  // Indicate that the wheel event was unhandled.
+  InputEventAck unhandled_ack(InputEventAckSource::COMPOSITOR_THREAD,
+                              blink::WebInputEvent::kMouseWheel,
+                              INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  std::unique_ptr<IPC::Message> response1(
+      new InputHostMsg_HandleInputEvent_ACK(0, unhandled_ack));
+  host->OnMessageReceived(*response1);
+  ASSERT_EQ(2U, process_host->sink().message_count());
+  process_host->sink().ClearMessages();
+
+  // Send a wheel event with phaseEnded. When wheel scroll latching is enabled
+  // the event will be dropped and the mouse_wheel_end_dispatch_timer_ will
+  // start.
+  NSEvent* wheelEvent2 =
+      MockScrollWheelEventWithPhase(@selector(phaseEnded), 0);
+  [view->cocoa_view() scrollWheel:wheelEvent2];
+  ASSERT_EQ(0U, process_host->sink().message_count());
+  DCHECK(view->HasPendingWheelEndEvent());
+  process_host->sink().ClearMessages();
+
+  host->ShutdownAndDestroyWidget(true);
+}
+
+TEST_F(RenderWidgetHostViewMacWithWheelScrollLatchingEnabledTest,
+       WheelWithMomentumPhaseBeganStopsTheWheelEndDispatchTimer) {
+  // Initialize the view associated with a MockRenderWidgetHostImpl, rather than
+  // the MockRenderProcessHost that is set up by the test harness which mocks
+  // out |OnMessageReceived()|.
+  TestBrowserContext browser_context;
+  MockRenderProcessHost* process_host =
+      new MockRenderProcessHost(&browser_context);
+  process_host->Init();
+  MockRenderWidgetHostDelegate delegate;
+  int32_t routing_id = process_host->GetNextRoutingID();
+  MockRenderWidgetHostImpl* host =
+      new MockRenderWidgetHostImpl(&delegate, process_host, routing_id);
+  RenderWidgetHostViewMac* view = new RenderWidgetHostViewMac(host, false);
+  process_host->sink().ClearMessages();
+
+  // Send an initial wheel event for scrolling by 3 lines.
+  NSEvent* wheelEvent1 =
+      MockScrollWheelEventWithPhase(@selector(phaseBegan), 3);
+  [view->cocoa_view() scrollWheel:wheelEvent1];
+  ASSERT_EQ(1U, process_host->sink().message_count());
+  process_host->sink().ClearMessages();
+
+  // Indicate that the wheel event was unhandled.
+  InputEventAck unhandled_ack(InputEventAckSource::COMPOSITOR_THREAD,
+                              blink::WebInputEvent::kMouseWheel,
+                              INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  std::unique_ptr<IPC::Message> response1(
+      new InputHostMsg_HandleInputEvent_ACK(0, unhandled_ack));
+  host->OnMessageReceived(*response1);
+  ASSERT_EQ(2U, process_host->sink().message_count());
+  process_host->sink().ClearMessages();
+
+  // Send a wheel event with phaseEnded. When wheel scroll latching is enabled
+  // the event will be dropped and the mouse_wheel_end_dispatch_timer_ will
+  // start.
+  NSEvent* wheelEvent2 =
+      MockScrollWheelEventWithPhase(@selector(phaseEnded), 0);
+  [view->cocoa_view() scrollWheel:wheelEvent2];
+  ASSERT_EQ(0U, process_host->sink().message_count());
+  DCHECK(view->HasPendingWheelEndEvent());
+  process_host->sink().ClearMessages();
+
+  // Send a wheel event with momentum phase started, this should stop the wheel
+  // end dispatch timer.
+  NSEvent* wheelEvent3 =
+      MockScrollWheelEventWithMomentumPhase(@selector(phaseBegan), 3);
+  ASSERT_TRUE(wheelEvent3);
+  [view->cocoa_view() scrollWheel:wheelEvent3];
+  ASSERT_EQ(1U, process_host->sink().message_count());
+  DCHECK(!view->HasPendingWheelEndEvent());
+  process_host->sink().ClearMessages();
+
+  host->ShutdownAndDestroyWidget(true);
+}
+
+TEST_F(RenderWidgetHostViewMacWithWheelScrollLatchingEnabledTest,
+       WheelWithPhaseBeganDispatchesThePendingWheelEnd) {
+  // Initialize the view associated with a MockRenderWidgetHostImpl, rather than
+  // the MockRenderProcessHost that is set up by the test harness which mocks
+  // out |OnMessageReceived()|.
+  TestBrowserContext browser_context;
+  MockRenderProcessHost* process_host =
+      new MockRenderProcessHost(&browser_context);
+  process_host->Init();
+  MockRenderWidgetHostDelegate delegate;
+  int32_t routing_id = process_host->GetNextRoutingID();
+  MockRenderWidgetHostImpl* host =
+      new MockRenderWidgetHostImpl(&delegate, process_host, routing_id);
+  RenderWidgetHostViewMac* view = new RenderWidgetHostViewMac(host, false);
+  process_host->sink().ClearMessages();
+
+  // Send an initial wheel event for scrolling by 3 lines.
+  NSEvent* wheelEvent1 =
+      MockScrollWheelEventWithPhase(@selector(phaseBegan), 3);
+  [view->cocoa_view() scrollWheel:wheelEvent1];
+  ASSERT_EQ(1U, process_host->sink().message_count());
+  process_host->sink().ClearMessages();
+
+  // Indicate that the wheel event was unhandled.
+  InputEventAck unhandled_ack(InputEventAckSource::COMPOSITOR_THREAD,
+                              blink::WebInputEvent::kMouseWheel,
+                              INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  std::unique_ptr<IPC::Message> response1(
+      new InputHostMsg_HandleInputEvent_ACK(0, unhandled_ack));
+  host->OnMessageReceived(*response1);
+  ASSERT_EQ(2U, process_host->sink().message_count());
+  process_host->sink().ClearMessages();
+
+  // Send a wheel event with phaseEnded. When wheel scroll latching is enabled
+  // the event will be dropped and the mouse_wheel_end_dispatch_timer_ will
+  // start.
+  NSEvent* wheelEvent2 =
+      MockScrollWheelEventWithPhase(@selector(phaseEnded), 0);
+  [view->cocoa_view() scrollWheel:wheelEvent2];
+  ASSERT_EQ(0U, process_host->sink().message_count());
+  DCHECK(view->HasPendingWheelEndEvent());
+  process_host->sink().ClearMessages();
+
+  // Send a wheel event with phase started, this should stop the wheel end
+  // dispatch timer and dispatch the pending wheel end event for the previous
+  // scroll sequence.
+  NSEvent* wheelEvent3 =
+      MockScrollWheelEventWithPhase(@selector(phaseBegan), 3);
+  ASSERT_TRUE(wheelEvent3);
+  [view->cocoa_view() scrollWheel:wheelEvent3];
+  ASSERT_EQ(2U, process_host->sink().message_count());
+  DCHECK(!view->HasPendingWheelEndEvent());
+  process_host->sink().ClearMessages();
+
+  host->ShutdownAndDestroyWidget(true);
+}
+
 class RenderWidgetHostViewMacPinchTest : public RenderWidgetHostViewMacTest {
  public:
   RenderWidgetHostViewMacPinchTest() : process_host_(nullptr) {}