Record size of scroller that user scrolls

cc/trees/layer_tree_host_impl_unittest.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
+#include "base/test/histogram_tester.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "cc/animation/animation_host.h"
 #include "cc/animation/animation_id_provider.h"
 #include "cc/animation/transform_operations.h"
 #include "cc/base/math_util.h"
 #include "cc/input/browser_controls_offset_manager.h"
 #include "cc/input/main_thread_scrolling_reason.h"
 #include "cc/input/page_scale_animation.h"
 #include "cc/layers/append_quads_data.h"
 #include "cc/layers/heads_up_display_layer_impl.h"
@@ skipping 719 matching lines @@
   ASSERT_EQ(scroll_info->scrolls.size(), 1u);
   EXPECT_TRUE(ScrollInfoContains(*scroll_info, root->id(),
                                  scroll_delta + scroll_delta2));
 
   root->ScrollBy(gfx::Vector2d());
   scroll_info = host_impl_->ProcessScrollDeltas();
   EXPECT_TRUE(ScrollInfoContains(*scroll_info, root->id(),
                                  scroll_delta + scroll_delta2));
 }
 
+TEST_F(LayerTreeHostImplTest, ScrollerSizeOfCCScrollingHistogramRecordingTest) {
+  SetupScrollAndContentsLayers(gfx::Size(800, 600));

[bokan, 2017/04/20 19:27:58]

Please use CreateBasicVirtualViewportLayers - it creates a layer tree closer to
what we use in production. And sets the viewport size and some other stuff that
you seem to be doing manually.

[yigu, 2017/04/20 20:22:35]

Done.

+  host_impl_->SetViewportSize(gfx::Size(500, 500));
+  DrawFrame();
+
+  LayerImpl* outer_viewport_scroll_layer =
+      host_impl_->active_tree()->OuterViewportScrollLayer();
+  int id = outer_viewport_scroll_layer->id();
+  std::unique_ptr<LayerImpl> child =
+      LayerImpl::Create(host_impl_->active_tree(), id + 2);
+  std::unique_ptr<LayerImpl> child_clip =
+      LayerImpl::Create(host_impl_->active_tree(), id + 3);
+
+  child_clip->SetBounds(gfx::Size(100, 100));
+
+  child->SetScrollClipLayer(child_clip->id());
+  child->SetElementId(LayerIdToElementIdForTesting(child->id()));
+  child->SetBounds(gfx::Size(100, 400));
+  child->SetPosition(gfx::PointF());
+  child->SetDrawsContent(true);
+
+  child_clip->test_properties()->AddChild(std::move(child));
+  outer_viewport_scroll_layer->test_properties()->AddChild(
+      std::move(child_clip));
+  host_impl_->active_tree()->BuildPropertyTreesForTesting();
+
+  base::HistogramTester histogram_tester;
+
+  // Test touch scroll.
+  InputHandler::ScrollStatus status = host_impl_->ScrollBegin(
+      BeginState(gfx::Point()).get(), InputHandler::TOUCHSCREEN);
+  EXPECT_EQ(InputHandler::SCROLL_ON_IMPL_THREAD, status.thread);
+  EXPECT_EQ(MainThreadScrollingReason::kNotScrollingOnMain,
+            status.main_thread_scrolling_reasons);
+  host_impl_->ScrollBy(UpdateState(gfx::Point(), gfx::Vector2d(0, 10)).get());
+  host_impl_->ScrollEnd(EndState().get());
+
+  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.
+  host_impl_->ScrollBegin(BeginState(gfx::Point(450, 450)).get(),
+                          InputHandler::TOUCHSCREEN);
+  host_impl_->ScrollBy(UpdateState(gfx::Point(), gfx::Vector2d(0, 10)).get());
+  host_impl_->ScrollEnd(EndState().get());
+  histogram_tester.ExpectTotalCount("Event.Scroll.ScrollerSize.OnScroll_Touch",
+                                    1);
+
+  // Test wheel scroll.
+  host_impl_->ScrollBegin(BeginState(gfx::Point()).get(), InputHandler::WHEEL);
+  host_impl_->ScrollBy(UpdateState(gfx::Point(), gfx::Vector2d(0, 10)).get());
+  host_impl_->ScrollEnd(EndState().get());
+  histogram_tester.ExpectBucketCount("Event.Scroll.ScrollerSize.OnScroll_Wheel",
+                                     10000, 1);
+  histogram_tester.ExpectTotalCount("Event.Scroll.ScrollerSize.OnScroll_Wheel",
+                                    1);
+}
+
 TEST_F(LayerTreeHostImplTest, ScrollRootCallsCommitAndRedraw) {
   SetupScrollAndContentsLayers(gfx::Size(100, 100));
   host_impl_->active_tree()->BuildPropertyTreesForTesting();
 
   host_impl_->SetViewportSize(gfx::Size(50, 50));
   DrawFrame();
 
   InputHandler::ScrollStatus status = host_impl_->ScrollBegin(
       BeginState(gfx::Point()).get(), InputHandler::WHEEL);
   EXPECT_EQ(InputHandler::SCROLL_ON_IMPL_THREAD, status.thread);
@@ skipping 11550 matching lines @@
     else
       EXPECT_FALSE(tile->HasRasterTask());
   }
   Region expected_invalidation(
       raster_source->GetRectForImage(checkerable_image->uniqueID()));
   EXPECT_EQ(expected_invalidation, *(root->GetPendingInvalidation()));
 }
 
 }  // namespace
 }  // namespace cc