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

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

Index: third_party/WebKit/Source/core/input/EventHandlerTest.cpp
diff --git a/third_party/WebKit/Source/core/input/EventHandlerTest.cpp b/third_party/WebKit/Source/core/input/EventHandlerTest.cpp
index 2161408f393ec7d446dfdfd76ba156d7e96eecda..5923ef873be729ef7758889399fc79cd1642b74c 100644
--- a/third_party/WebKit/Source/core/input/EventHandlerTest.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandlerTest.cpp
@@ -16,6 +16,7 @@
 #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 {
@@ -79,6 +80,29 @@ class MousePressEventBuilder : public WebMouseEvent {
   }
 };
 
+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();
+    sourceDevice = device;
+    m_frameScale = 1;
+  }
+};
+
+class ScrollEndEventBuilder : public WebGestureEvent {
+ public:
+  ScrollEndEventBuilder() : WebGestureEvent() {
+    m_type = WebInputEvent::GestureScrollEnd;
+    m_frameScale = 1;
+  }
+};
+
 void EventHandlerTest::SetUp() {
   m_dummyPageHolder = DummyPageHolder::create(IntSize(300, 400));
 }
@@ -461,6 +485,114 @@ TEST_F(EventHandlerTest, dragEndInNewDrag) {
   // This test passes if it doesn't crash.
 }
 
+TEST_F(EventHandlerTest, NonCompositedMainThreadScrollingReasonTest) {
+  setHtmlInnerHTML(
+      "<style>.box { overflow:scroll; width: 100px; height: 100px; }"
+      " .translucent { opacity: 0.5; }"
+      " .spacer { height: 1000px; }"
+      " .composited { will-change: transform; }"
+      " .hidden { overflow: hidden; }"
+      "</style>"
+      "<div id='box' class='translucent box'><div class='spacer'></div></div>"
+      "<div class='composited translucent box'>"
+      " <div class='spacer'></div>"
+      "</div>");
+
+  page().settings().setAcceleratedCompositingEnabled(true);
+  document().view()->setParentVisible(true);
+  document().view()->setSelfVisible(true);
+  document().view()->updateAllLifecyclePhases();
+
+  HistogramTester histogramTester;
+
+  // Test touch scroll.
+  ScrollBeginEventBuilder touchScrollBegin(
+      IntPoint(50, 50), FloatPoint(0.f, 1.f), WebGestureDeviceTouchscreen);
+  ScrollEndEventBuilder touchScrollEnd;
+  document().frame()->eventHandler().handleGestureEvent(touchScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(touchScrollEnd);
+  histogramTester.expectBucketCount("Renderer4.MainThreadGestureScrollReason",
+                                    17, 1);
+
+  document().frame()->eventHandler().handleGestureEvent(touchScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(touchScrollEnd);
+  histogramTester.expectBucketCount("Renderer4.MainThreadGestureScrollReason",
+                                    17, 2);
+
+  // Test wheel scroll.
+  ScrollBeginEventBuilder wheelScrollBegin(
+      IntPoint(50, 50), FloatPoint(0.f, 1.f), WebGestureDeviceTouchpad);
+  ScrollEndEventBuilder wheelScrollEnd;
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollEnd);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 17,
+                                    1);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 19,
+                                    1);
+  histogramTester.expectTotalCount("Renderer4.MainThreadWheelScrollReason", 2);
+
+  Element* box = document().getElementById("box");
+  box->setAttribute("class", "hidden");

[bokan, 2017/04/07 17:39:03]

This is testing my request for non-scrollable areas right? Please split it out
into a separate test. Long tests that test multiple things are hard to reason
about and difficult to debug when things break. Prefer many small, specific
tests to few large ones.

[yigu, 2017/04/07 19:26:27]

Done.

+  document().view()->updateAllLifecyclePhases();
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollEnd);
+  histogramTester.expectTotalCount("Renderer4.MainThreadWheelScrollReason", 2);
+
+  wheelScrollBegin.y = wheelScrollBegin.globalY = 150;
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollEnd);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 17,

[bokan, 2017/04/07 17:39:03]

Please use names for the bucket constants here. You can just define a function
above that converts the enums to bucket index.

[yigu, 2017/04/07 19:26:27]

Done.

+                                    1);
+}
+
+TEST_F(EventHandlerTest,
+       NonCompositedMainThreadScrollingReasonWithNestedScrollersTest) {
+  setHtmlInnerHTML(
+      "<style>.container { overflow:scroll; width: 200px; height: 200px; }"

[bokan, 2017/04/07 17:39:03]

nit: .container should be on new line

[yigu, 2017/04/07 19:26:27]

Done.

+      " .box { overflow:scroll; width: 100px; height: 100px; }"
+      " .translucent { opacity: 0.5; }"
+      " .with-border-radius { border: 5px solid; border-radius: 5px; }"
+      " .spacer { height: 1000px; }"
+      " .composited { will-change: transform; }"
+      "</style>"
+      "<div id='container' class='translucent container'>"
+      "  <div class='composited box'>"
+      "    <div class='box with-border-radius'>"

[bokan, 2017/04/07 17:39:03]

You're testing the non-scrollable case here as well as mixing
composited/non-composited. Split up into separate tests.

[yigu, 2017/04/07 19:26:27]

Done.

+      "      <div class='spacer'></div>"
+      "    </div>"
+      "  </div>"
+      "  <div class='composited translucent box'></div>"
+      "</div>");
+
+  page().settings().setAcceleratedCompositingEnabled(true);
+  document().view()->setParentVisible(true);
+  document().view()->setSelfVisible(true);
+  document().view()->updateAllLifecyclePhases();
+
+  HistogramTester histogramTester;
+
+  ScrollBeginEventBuilder wheelScrollBegin(
+      IntPoint(50, 50), FloatPoint(0.f, 1.f), WebGestureDeviceTouchpad);
+  ScrollEndEventBuilder wheelScrollEnd;
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollEnd);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 17,
+                                    1);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 19,
+                                    1);
+  histogramTester.expectBucketCount("Renderer4.MainThreadWheelScrollReason", 20,
+                                    1);
+  histogramTester.expectTotalCount("Renderer4.MainThreadWheelScrollReason", 3);
+
+  Element* container = document().getElementById("container");
+  container->setAttribute("class", "composited");

[bokan, 2017/04/07 17:39:03]

Ditto for the will-change bit here. Split it out into a separate test.

[yigu, 2017/04/07 19:26:27]

Done.

+  document().view()->updateAllLifecyclePhases();
+  wheelScrollBegin.y = wheelScrollBegin.globalY = 150;
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollBegin);
+  document().frame()->eventHandler().handleGestureEvent(wheelScrollEnd);
+  histogramTester.expectTotalCount("Renderer4.MainThreadWheelScrollReason", 3);
+}
+
 class TooltipCapturingChromeClient : public EmptyChromeClient {
  public:
   TooltipCapturingChromeClient() {}