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 d71e2f1f94d0deec3185ed2c1d920ee3b7623f4e..fd1d83710e613c6562a55c148db4514b11f6f1ee 100644
--- a/third_party/WebKit/Source/core/input/EventHandlerTest.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandlerTest.cpp
@@ -5,6 +5,7 @@
 #include "core/input/EventHandler.h"
 
 #include <memory>
+#include "core/dom/ClientRect.h"
 #include "core/dom/Document.h"
 #include "core/dom/Range.h"
 #include "core/editing/Editor.h"
@@ -12,12 +13,34 @@
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
+#include "core/layout/LayoutBox.h"
 #include "core/loader/EmptyClients.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/Page.h"
+#include "core/paint/PaintLayerScrollableArea.h"
 #include "core/testing/DummyPageHolder.h"
+#include "platform/scroll/MainThreadScrollingReason.h"
+#include "platform/testing/HistogramTester.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#define EXPECT_WHEEL_BUCKET(reason, count)     \
+  histogram_tester.ExpectBucketCount(          \
+      "Renderer4.MainThreadWheelScrollReason", \
+      GetBucketIndex(MainThreadScrollingReason::reason), count);
+
+#define EXPECT_TOUCH_BUCKET(reason, count)       \
+  histogram_tester.ExpectBucketCount(            \
+      "Renderer4.MainThreadGestureScrollReason", \
+      GetBucketIndex(MainThreadScrollingReason::reason), count);
+
+#define EXPECT_WHEEL_TOTAL(count)                                            \
+  histogram_tester.ExpectTotalCount("Renderer4.MainThreadWheelScrollReason", \
+                                    count);
+
+#define EXPECT_TOUCH_TOTAL(count)                                              \
+  histogram_tester.ExpectTotalCount("Renderer4.MainThreadGestureScrollReason", \
+                                    count);
+
 namespace blink {
 
 class EventHandlerTest : public ::testing::Test {
@@ -36,6 +59,48 @@ class EventHandlerTest : public ::testing::Test {
   std::unique_ptr<DummyPageHolder> dummy_page_holder_;
 };
 
+class NonCompositedMainThreadScrollingReasonRecordTest
+    : public EventHandlerTest {
+ protected:
+  class ScrollBeginEventBuilder : public WebGestureEvent {
+   public:
+    ScrollBeginEventBuilder(IntPoint position,
+                            FloatPoint delta,
+                            WebGestureDevice device)
+        : WebGestureEvent() {
+      type_ = WebInputEvent::kGestureScrollBegin;
+      x = global_x = position.X();
+      y = global_y = position.Y();
+      data.scroll_begin.delta_y_hint = delta.Y();
+      source_device = device;
+      frame_scale_ = 1;
+    }
+  };
+
+  class ScrollUpdateEventBuilder : public WebGestureEvent {
+   public:
+    ScrollUpdateEventBuilder() : WebGestureEvent() {
+      type_ = WebInputEvent::kGestureScrollUpdate;
+      data.scroll_update.delta_x = 0.0f;
+      data.scroll_update.delta_y = 1.0f;
+      data.scroll_update.velocity_x = 0;
+      data.scroll_update.velocity_y = 1;
+      frame_scale_ = 1;
+    }
+  };
+
+  class ScrollEndEventBuilder : public WebGestureEvent {
+   public:
+    ScrollEndEventBuilder() : WebGestureEvent() {
+      type_ = WebInputEvent::kGestureScrollEnd;
+      frame_scale_ = 1;
+    }
+  };
+
+  int GetBucketIndex(uint32_t reason);
+  void Scroll(Element*, const WebGestureDevice);
+};
+
 class TapEventBuilder : public WebGestureEvent {
  public:
   TapEventBuilder(IntPoint position, int tap_count)
@@ -90,6 +155,34 @@ void EventHandlerTest::SetHtmlInnerHTML(const char* html_content) {
   GetDocument().View()->UpdateAllLifecyclePhases();
 }
 
+int NonCompositedMainThreadScrollingReasonRecordTest::GetBucketIndex(
+    uint32_t reason) {
+  int index = 1;
+  while (!(reason & 1)) {
+    reason >>= 1;
+    ++index;
+  }
+  DCHECK_EQ(reason, 1u);
+  return index;
+}
+
+void NonCompositedMainThreadScrollingReasonRecordTest::Scroll(
+    Element* element,
+    const WebGestureDevice device) {
+  DCHECK(element);
+  DCHECK(element->getBoundingClientRect());
+  ClientRect* rect = element->getBoundingClientRect();
+  ScrollBeginEventBuilder scroll_begin(
+      IntPoint(rect->left() + rect->width() / 2,
+               rect->top() + rect->height() / 2),
+      FloatPoint(0.f, 1.f), device);
+  ScrollUpdateEventBuilder scroll_update;
+  ScrollEndEventBuilder scroll_end;
+  GetDocument().GetFrame()->GetEventHandler().HandleGestureEvent(scroll_begin);
+  GetDocument().GetFrame()->GetEventHandler().HandleGestureEvent(scroll_update);
+  GetDocument().GetFrame()->GetEventHandler().HandleGestureEvent(scroll_end);
+}
+
 TEST_F(EventHandlerTest, dragSelectionAfterScroll) {
   SetHtmlInnerHTML(
       "<style> body { margin: 0px; } .upper { width: 300px; height: 400px; }"
@@ -548,4 +641,145 @@ TEST_F(EventHandlerTooltipTest, mouseLeaveClearsTooltip) {
   EXPECT_EQ(WTF::String(), LastToolTip());
 }
 
+TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
+       TouchAndWheelGeneralTest) {
+  SetHtmlInnerHTML(
+      "<style>"
+      " .box { overflow:scroll; width: 100px; height: 100px; }"
+      " .translucent { opacity: 0.5; }"
+      " .spacer { height: 1000px; }"
+      "</style>"
+      "<div id='box' class='translucent box'>"
+      " <div class='spacer'></div>"
+      "</div>");
+
+  GetDocument().View()->UpdateAllLifecyclePhases();
+
+  Element* box = GetDocument().getElementById("box");
+  HistogramTester histogram_tester;
+
+  // Test touch scroll.
+  Scroll(box, kWebGestureDeviceTouchscreen);
+  EXPECT_TOUCH_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_TOUCH_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+
+  Scroll(box, kWebGestureDeviceTouchscreen);
+  EXPECT_TOUCH_BUCKET(kHasOpacityAndLCDText, 2);
+  EXPECT_TOUCH_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 2);
+  EXPECT_TOUCH_TOTAL(4);
+
+  // Test wheel scroll.
+  Scroll(box, kWebGestureDeviceTouchpad);
+  EXPECT_WHEEL_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_TOTAL(2);
+}
+
+TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
+       CompositedScrollableAreaTest) {
+  SetHtmlInnerHTML(
+      "<style>"
+      " .box { overflow:scroll; width: 100px; height: 100px; }"
+      " .translucent { opacity: 0.5; }"
+      " .composited { will-change: transform; }"
+      " .spacer { height: 1000px; }"
+      "</style>"
+      "<div id='box' class='translucent box'>"
+      " <div class='spacer'></div>"
+      "</div>");
+
+  GetPage().GetSettings().SetAcceleratedCompositingEnabled(true);
+  GetDocument().View()->SetParentVisible(true);
+  GetDocument().View()->SetSelfVisible(true);
+  GetDocument().View()->UpdateAllLifecyclePhases();
+
+  Element* box = GetDocument().getElementById("box");
+  HistogramTester histogram_tester;
+
+  Scroll(box, kWebGestureDeviceTouchpad);
+  EXPECT_WHEEL_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_TOTAL(2);
+
+  box->setAttribute("class", "composited translucent box");
+  GetDocument().View()->UpdateAllLifecyclePhases();
+  Scroll(box, kWebGestureDeviceTouchpad);
+  EXPECT_FALSE(ToLayoutBox(box->GetLayoutObject())
+                   ->GetScrollableArea()
+                   ->GetNonCompositedMainThreadScrollingReasons());
+  EXPECT_WHEEL_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_TOTAL(2);
+}
+
+TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
+       NotScrollableAreaTest) {
+  SetHtmlInnerHTML(
+      "<style>.box { overflow:scroll; width: 100px; height: 100px; }"
+      " .translucent { opacity: 0.5; }"
+      " .hidden { overflow: hidden; }"
+      " .spacer { height: 1000px; }"
+      "</style>"
+      "<div id='box' class='translucent box'>"
+      " <div class='spacer'></div>"
+      "</div>");
+
+  GetDocument().View()->UpdateAllLifecyclePhases();
+
+  Element* box = GetDocument().getElementById("box");
+  HistogramTester histogram_tester;
+
+  Scroll(box, kWebGestureDeviceTouchpad);
+  EXPECT_WHEEL_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_TOTAL(2);
+
+  box->setAttribute("class", "hidden translucent box");
+  GetDocument().View()->UpdateAllLifecyclePhases();
+  Scroll(box, kWebGestureDeviceTouchpad);
+  EXPECT_WHEEL_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_TOTAL(2);
+}
+
+TEST_F(NonCompositedMainThreadScrollingReasonRecordTest, NestedScrollersTest) {
+  SetHtmlInnerHTML(
+      "<style>"
+      " .container { overflow:scroll; width: 200px; height: 200px; }"
+      " .box { overflow:scroll; width: 100px; height: 100px; }"
+      " .translucent { opacity: 0.5; }"
+      " .transform { transform: scale(0.8); }"
+      " .with-border-radius { border: 5px solid; border-radius: 5px; }"
+      " .spacer { height: 1000px; }"
+      " .composited { will-change: transform; }"
+      "</style>"
+      "<div id='container' class='container with-border-radius'>"
+      "  <div class='translucent box'>"
+      "    <div id='inner' class='composited transform box'>"
+      "      <div class='spacer'></div>"
+      "    </div>"
+      "    <div class='spacer'></div>"
+      "  </div>"
+      "  <div class='spacer'></div>"
+      "</div>");
+
+  GetPage().GetSettings().SetAcceleratedCompositingEnabled(true);
+  GetDocument().View()->SetParentVisible(true);
+  GetDocument().View()->SetSelfVisible(true);
+  GetDocument().View()->UpdateAllLifecyclePhases();
+
+  Element* box = GetDocument().getElementById("inner");
+  HistogramTester histogram_tester;
+
+  Scroll(box, kWebGestureDeviceTouchpad);
+  // Scrolling the inner box will gather reasons from the scrolling chain. The
+  // inner box itself has no reason because it's composited. Other scrollable
+  // areas from the chain have corresponding reasons.
+  EXPECT_WHEEL_BUCKET(kHasOpacityAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kHasBorderRadius, 1);
+  EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 0);
+  EXPECT_WHEEL_TOTAL(3);
+}
+
 }  // namespace blink