re-land the "SourceEventType added to LatencyInfo."

content/browser/renderer_host/render_widget_host_view_mac_unittest.mm

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <Cocoa/Cocoa.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <tuple>
@@ skipping 885 matching lines @@
   NSEvent* wheelEvent2 = MockScrollWheelEventWithPhase(@selector(phaseEnded),0);
   [view->cocoa_view() scrollWheel:wheelEvent2];
   ui::LatencyInfo::LatencyComponent ui_component2;
   ASSERT_TRUE(host->lastWheelEventLatencyInfo.FindLatency(
       ui::INPUT_EVENT_LATENCY_UI_COMPONENT, 0, &ui_component2) );
 
   // Clean up.
   host->ShutdownAndDestroyWidget(true);
 }
 
+TEST_F(RenderWidgetHostViewMacTest, SourceEventTypeExistsInLatencyInfo) {
+  // 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 a wheel event for scrolling by 3 lines.
+  // Verifies that SourceEventType exists in forwarded LatencyInfo object.
+  NSEvent* wheelEvent = MockScrollWheelEventWithPhase(@selector(phaseBegan), 3);
+  [view->cocoa_view() scrollWheel:wheelEvent];
+  ASSERT_TRUE(host->lastWheelEventLatencyInfo.source_event_type() ==
+              ui::SourceEventType::WHEEL);
+
+  // Clean up.
+  host->ShutdownAndDestroyWidget(true);
+}
+
 TEST_F(RenderWidgetHostViewMacTest, ScrollWheelEndEventDelivery) {
   // 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();
@@ skipping 541 matching lines @@
   // Repeat for the tab's view.
   [rwhv_cocoa_ setMarkedText:text
                selectedRange:selectedRange
             replacementRange:replacementRange];
   EXPECT_TRUE([rwhv_cocoa_ hasMarkedText]);
   rwhv_mac_->ImeCancelComposition();
   EXPECT_FALSE([rwhv_cocoa_ hasMarkedText]);
 }
 
 }  // namespace content