Record size of scroller that user scrolls

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/ClientRect.h"
 #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/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/scroll/ScrollerSize.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(            \
@@ skipping 12 matching lines @@
 
 class EventHandlerTest : public ::testing::Test {
  protected:
   void SetUp() override;
 
   Page& GetPage() const { return dummy_page_holder_->GetPage(); }
   Document& GetDocument() const { return dummy_page_holder_->GetDocument(); }
   FrameSelection& Selection() const {
     return GetDocument().GetFrame()->Selection();
   }
-
   void SetHtmlInnerHTML(const char* html_content);
+  void Scroll(Element*, const WebGestureDevice);
 
  protected:
   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)
       : WebGestureEvent(WebInputEvent::kGestureTap,
                         WebInputEvent::kNoModifiers,
                         TimeTicks::Now().InSeconds()) {
     x = global_x = position.X();
     y = global_y = position.Y();
@@ skipping 27 matching lines @@
                       WebInputEvent::kNoModifiers,
                       TimeTicks::Now().InSeconds()) {
     click_count = click_count_param;
     button = button_param;
     SetPositionInWidget(position_param.X(), position_param.Y());
     SetPositionInScreen(position_param.X(), position_param.Y());
     frame_scale_ = 1;
   }
 };
 
+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;
+  }
+};
+
 void EventHandlerTest::SetUp() {
   dummy_page_holder_ = DummyPageHolder::Create(IntSize(300, 400));
 }
 
 void EventHandlerTest::SetHtmlInnerHTML(const char* html_content) {
   GetDocument().documentElement()->setInnerHTML(String::FromUTF8(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) {
+void EventHandlerTest::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);
@@ skipping 392 matching lines @@
       WebInputEvent::kMouseUp, WebFloatPoint(100, 50), WebFloatPoint(200, 250),
       WebPointerProperties::Button::kLeft, 1, WebInputEvent::kNoModifiers,
       TimeTicks::Now().InSeconds());
   mouse_up_event.SetFrameScale(1);
   GetDocument().GetFrame()->GetEventHandler().DragSourceEndedAt(
       mouse_up_event, kDragOperationNone);
 
   // This test passes if it doesn't crash.
 }
 
+TEST_F(EventHandlerTest,
+       ScrollerSizeOfMainThreadScrollingHistogramRecordingTest) {
+  SetHtmlInnerHTML(
+      "<style>"
+      " .container { width: 200px; height: 200px; overflow: scroll; }"
+      " .box { width: 100px; height: 100px; overflow: scroll; }"
+      " .spacer { height: 1000px;} body { height: 2000px; }"
+      "</style>"
+      "<div class='container'>"
+      " <div id='box' class='box'>"
+      "  <div id='content' class='spacer'></div>"
+      " </div>"
+      "</div>");
+
+  Element* box = GetDocument().getElementById("box");
+  HistogramTester histogram_tester;
+
+  // Test wheel scroll on the box.
+  Scroll(box, kWebGestureDeviceTouchpad);
+  histogram_tester.ExpectBucketCount("Event.Scroll.ScrollerSize.OnScroll_Wheel",
+                                     10000, 1);
+  // Only the first scrollable area is recorded.
+  histogram_tester.ExpectBucketCount("Event.Scroll.ScrollerSize.OnScroll_Wheel",
+                                     40000, 0);
+  histogram_tester.ExpectTotalCount("Event.Scroll.ScrollerSize.OnScroll_Wheel",
+                                    1);
+
+  // Test touch scroll on the main frame.

[bokan, 2017/04/18 19:24:39]

You're not trying to scroll the main frame here though, right?

[yigu, 2017/04/19 20:53:05]

No.

+  Scroll(box, kWebGestureDeviceTouchscreen);
+  histogram_tester.ExpectBucketCount("Event.Scroll.ScrollerSize.OnScroll_Touch",
+                                     10000, 1);
+  histogram_tester.ExpectTotalCount("Event.Scroll.ScrollerSize.OnScroll_Touch",
+                                    1);
+
+  // Scrolling root layer doesn't add to count.
+  Element* body = GetDocument().body();
+  Scroll(body, kWebGestureDeviceTouchscreen);

[bokan, 2017/04/18 19:24:39]

In general, this won't work since Scroll() will send an event to the middle of
the given box - it doesn't meant that box will be scrolled (e.g. .box or
.container might be at the middle coordinate). This may or may not work in this
case but you may want to add ASSERTS to check that the box that you're expecting
to scroll actually got scrolled. Both for your own assurance and the reader's

[yigu, 2017/04/19 20:53:05]

In general it may not work. But in the example above, scrolling in the center of
an element works. I added an ASSERT as you suggested in the function Scroll to
guarantee that.

+  histogram_tester.ExpectBucketCount("Event.Scroll.ScrollerSize.OnScroll_Touch",
+                                     kMaxScrollerSize, 0);
+  histogram_tester.ExpectTotalCount("Event.Scroll.ScrollerSize.OnScroll_Touch",
+                                    1);
+}
+
 class TooltipCapturingChromeClient : public EmptyChromeClient {
  public:
   TooltipCapturingChromeClient() {}
 
   void SetToolTip(LocalFrame&, const String& str, TextDirection) override {
     last_tool_tip_ = str;
   }
 
   String& LastToolTip() { return last_tool_tip_; }
 
@@ skipping 182 matching lines @@
   // 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