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..df007785dbd6b7b87f12e451de634f3c09014482 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);

[tdresser, 2017/04/11 18:50:47]

I'm not sure it's worth factoring these out.
Could we declare a few constants (histogram name, bucket index), instead?

[bokan, 2017/04/11 19:23:26]

I asked for this so I'll explain my reasoning. I like the fact that a macro like
this clearly stands out from the surrounding code as checking an expectation,
whereas histogram_tester.ExpectTotalCount(...) blends in with control code. It
also reduces the amount of boilerplate so is much easier to read.

Constants help somewhat with the latter (though harder to keep to one line) but
not the former. Given that expectation macros are quite common in our tests (in
fact, all gtest.h checks are macros) I'm more partial to keeping these, WDYT?

[tdresser, 2017/04/11 20:33:27]

In general, use of macros like this is discouraged
(https://google.github.io/styleguide/cppguide.html#Preprocessor_Macros).

Ideally we'd be able to write a function that returned an assertion result here,
but the way histogram tester is written, we can't really do that.
This would let us write:
EXPECT_THAT(TouchTotalEquals(5));

Which is the best of both worlds, IMO.

If you prefer the macros here, fine by me.

[yigu, 2017/04/11 21:28:10]

Macros help to locate the exact line that causes crashes or fails expectations.
For a test maybe we can just use them.

[bokan, 2017/04/11 22:27:16]

Yes, histogram_tester is unfortunate in this way. IMHO, the macro arguments in
the style guide don't apply as strongly to tests and missing line numbers in
test failures is unacceptable so I think macros are preferable in this case.

+
 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 +641,144 @@ 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>"
+      "  <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