Move logic of recording main thread scrolling reasons from cc to blink::ScrollManager

third_party/WebKit/Source/core/input/EventHandlerTest.cpp

 // Copyright 2015 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 "core/input/EventHandler.h"
 
 #include <memory>
 #include "core/dom/Document.h"
 #include "core/dom/Range.h"
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/loader/EmptyClients.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/Page.h"
 #include "core/testing/DummyPageHolder.h"
+#include "platform/testing/HistogramTester.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 
 class EventHandlerTest : public ::testing::Test {
  protected:
   void SetUp() override;
 
   Page& page() const { return m_dummyPageHolder->page(); }
   Document& document() const { return m_dummyPageHolder->document(); }
@@ skipping 43 matching lines @@
                       WebInputEvent::NoModifiers,
                       TimeTicks::Now().InSeconds()) {
     clickCount = clickCountParam;
     button = buttonParam;
     x = globalX = position.x();
     y = globalY = position.y();
     m_frameScale = 1;
   }
 };
 
+class ScrollBeginEventBuilder : public WebGestureEvent {
+ public:
+  ScrollBeginEventBuilder(IntPoint position,
+                          FloatPoint delta,
+                          WebGestureDevice device)
+      : WebGestureEvent() {
+    m_type = WebInputEvent::GestureScrollBegin;
+    x = globalX = position.x();
+    y = globalY = position.y();
+    data.scrollBegin.deltaYHint = delta.y();
+    data.scrollBegin.targetViewport = true;

[bokan, 2017/03/28 15:30:15]

This should be false. It's used in Android WebView to send scrolls directly to
the viewport layers, skipping hit tests.

+    sourceDevice = device;
+    m_frameScale = 1;
+  }
+};
+
 void EventHandlerTest::SetUp() {
   m_dummyPageHolder = DummyPageHolder::create(IntSize(300, 400));
 }
 
 void EventHandlerTest::setHtmlInnerHTML(const char* htmlContent) {
   document().documentElement()->setInnerHTML(String::fromUTF8(htmlContent));
   document().view()->updateAllLifecyclePhases();
 }
 
 TEST_F(EventHandlerTest, dragSelectionAfterScroll) {
@@ skipping 362 matching lines @@
       WebInputEvent::MouseUp, WebFloatPoint(100, 50), WebFloatPoint(200, 250),
       WebPointerProperties::Button::Left, 1, WebInputEvent::NoModifiers,
       TimeTicks::Now().InSeconds());
   mouseUpEvent.setFrameScale(1);
   document().frame()->eventHandler().dragSourceEndedAt(mouseUpEvent,
                                                        DragOperationNone);
 
   // This test passes if it doesn't crash.
 }
 
+TEST_F(EventHandlerTest, NonCompositedMainThreadScrollingReasonTest) {
+  setHtmlInnerHTML(
+      "<style>.box { width: 100px; height: 100px; overflow: scroll; }"
+      ".translucent { opacity: 0.5; will-change:transform;} .spacer { height: "
+      "1000px;} body {height: 1000px; }"
+      ".border { border: 5px solid; border-radius: 2px; } </style>"
+      "<div class='translucent box'><div class='spacer'></div></div>"
+      "<div class='border box'><div class='spacer'></div></div>");

[bokan, 2017/03/28 15:30:15]

Please add at least one case that checks that a composited (and maybe main
thread scrolled) box doesn't add to the counts.

I'd also add a case where you have a composited scroller over a non-composited
scroller. I believe that should cause the scroll events to go to the main thread
even if scrolling over the composited box.

+
+  HistogramTester histogramTester;
+  // Test wheel scroll
+  ScrollBeginEventBuilder wheelScrollBegin(
+      IntPoint(50, 50), FloatPoint(0.f, 1.f), WebGestureDeviceTouchpad);
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 17,
+                                    1);
+
+  wheelScrollBegin.y = wheelScrollBegin.globalY = 150;
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);

[bokan, 2017/03/28 15:30:15]

You should send a ScrollEnd after each scrollBegin, just to make sure we don't
confuse the EventHandler.

+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 20,
+                                    1);
+  // Test touch scroll
+  ScrollBeginEventBuilder touchScrollBegin(
+      IntPoint(50, 50), FloatPoint(0.f, 1.f), WebGestureDeviceTouchscreen);
+  document().frame()->eventHandler().handleGestureEvent(touchScrollBegin);
+  histogramTester.expectBucketCount("Renderer4.MainThreadGestureScrollReason",
+                                    17, 1);
+
+  document().frame()->eventHandler().handleGestureEvent(touchScrollBegin);
+  histogramTester.expectBucketCount("Renderer4.MainThreadGestureScrollReason",
+                                    17, 2);
+}
+
 class TooltipCapturingChromeClient : public EmptyChromeClient {
  public:
   TooltipCapturingChromeClient() {}
 
   void setToolTip(LocalFrame&, const String& str, TextDirection) override {
     m_lastToolTip = str;
   }
 
   String& lastToolTip() { return m_lastToolTip; }
 
@@ skipping 40 matching lines @@
       WebInputEvent::MouseLeave, WebFloatPoint(0, 0), WebFloatPoint(0, 0),
       WebPointerProperties::Button::NoButton, 0, WebInputEvent::NoModifiers,
       TimeTicks::Now().InSeconds());
   mouseLeaveEvent.setFrameScale(1);
   document().frame()->eventHandler().handleMouseLeaveEvent(mouseLeaveEvent);
 
   EXPECT_EQ(WTF::String(), lastToolTip());
 }
 
 }  // namespace blink