CL for src perf tryjob to run smoothness.scrolling_tough_ad_cases benchmark on android-nexus5X plat…

cc/trees/layer_tree_host_impl.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 <stdint.h>
 
 #include <algorithm>
@@ skipping 2625 matching lines @@
   return ScrollBeginImpl(scroll_state, viewport()->MainScrollLayer(), type);
 }
 
 InputHandler::ScrollStatus LayerTreeHostImpl::ScrollBegin(
     ScrollState* scroll_state,
     InputHandler::ScrollInputType type) {
   ScrollStatus scroll_status;
   scroll_status.main_thread_scrolling_reasons =
       MainThreadScrollingReason::kNotScrollingOnMain;
   TRACE_EVENT0("cc", "LayerTreeHostImpl::ScrollBegin");
-
+  bool scroll_on_main_thread = false;
+  LayerImpl* scrolling_layer_impl;
   // On Mac a scroll begin with |inertial_phase| = true happens to handle a
   // fling.
-  if (scroll_state->is_in_inertial_phase())
-    return FlingScrollBegin();
+  if (scroll_state->is_in_inertial_phase()) {
+    scrolling_layer_impl = CurrentlyScrollingLayer();
+  } else {
+    ClearCurrentlyScrollingLayer();
 
-  ClearCurrentlyScrollingLayer();
+    gfx::Point viewport_point(scroll_state->position_x(),
+                              scroll_state->position_y());
+    gfx::PointF device_viewport_point = gfx::ScalePoint(
+        gfx::PointF(viewport_point), active_tree_->device_scale_factor());
+    LayerImpl* layer_impl =
+        active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
+    if (layer_impl) {
+      LayerImpl* scroll_layer_impl =
+          active_tree_->FindFirstScrollingLayerOrScrollbarLayerThatIsHitByPoint(
+              device_viewport_point);
+      if (scroll_layer_impl &&
+          !HasScrollAncestor(layer_impl, scroll_layer_impl)) {
+        scroll_status.thread = SCROLL_UNKNOWN;
+        scroll_status.main_thread_scrolling_reasons =
+            MainThreadScrollingReason::kFailedHitTest;
+        return scroll_status;
+      }
+    }
+    scrolling_layer_impl = FindScrollLayerForDeviceViewportPoint(
+        device_viewport_point, type, layer_impl, &scroll_on_main_thread,
+        &scroll_status.main_thread_scrolling_reasons);
 
-  gfx::Point viewport_point(scroll_state->position_x(),
-                            scroll_state->position_y());
-
-  gfx::PointF device_viewport_point = gfx::ScalePoint(
-      gfx::PointF(viewport_point), active_tree_->device_scale_factor());
-  LayerImpl* layer_impl =
-      active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
-
-  if (layer_impl) {
-    LayerImpl* scroll_layer_impl =
-        active_tree_->FindFirstScrollingLayerOrScrollbarLayerThatIsHitByPoint(
-            device_viewport_point);
-    if (scroll_layer_impl &&
-        !HasScrollAncestor(layer_impl, scroll_layer_impl)) {
-      scroll_status.thread = SCROLL_UNKNOWN;
-      scroll_status.main_thread_scrolling_reasons =
-          MainThreadScrollingReason::kFailedHitTest;
-      return scroll_status;
-    }
+    if (scrolling_layer_impl)
+      scroll_affects_scroll_handler_ =
+          scrolling_layer_impl->layer_tree_impl()->have_scroll_event_handlers();
   }
 
-  bool scroll_on_main_thread = false;
-  LayerImpl* scrolling_layer_impl = FindScrollLayerForDeviceViewportPoint(
-      device_viewport_point, type, layer_impl, &scroll_on_main_thread,
-      &scroll_status.main_thread_scrolling_reasons);
-
-  if (scrolling_layer_impl)
-    scroll_affects_scroll_handler_ =
-        scrolling_layer_impl->layer_tree_impl()->have_scroll_event_handlers();
-
   if (scroll_on_main_thread) {
     RecordCompositorSlowScrollMetric(type, MAIN_THREAD);
 
     scroll_status.thread = SCROLL_ON_MAIN_THREAD;
     return scroll_status;
   }
 
   return ScrollBeginImpl(scroll_state, scrolling_layer_impl, type);
 }
 
@@ skipping 477 matching lines @@
   accumulated_root_overscroll_ = gfx::Vector2dF();
 }
 
 void LayerTreeHostImpl::ScrollEnd(ScrollState* scroll_state) {
   DCHECK(scroll_state);
   DCHECK(scroll_state->delta_x() == 0 && scroll_state->delta_y() == 0);
 
   DistributeScrollDelta(scroll_state);
   top_controls_manager_->ScrollEnd();
 
-  if (scroll_state->is_in_inertial_phase()) {
+  if (!scroll_state->data()->fling_might_happen_next) {
     // Only clear the currently scrolling layer if we know the scroll is done.
-    // A non-inertial scroll end could be followed by an inertial scroll.
     ClearCurrentlyScrollingLayer();
   }
 }
 
 InputHandler::ScrollStatus LayerTreeHostImpl::FlingScrollBegin() {
   InputHandler::ScrollStatus scroll_status;
   scroll_status.main_thread_scrolling_reasons =
       MainThreadScrollingReason::kNotScrollingOnMain;
   if (!CurrentlyScrollingLayer()) {
     scroll_status.thread = SCROLL_IGNORED;
@@ skipping 894 matching lines @@
   if (is_visible) {
     worker_context_visibility_ =
         worker_context->CacheController()->ClientBecameVisible();
   } else {
     worker_context->CacheController()->ClientBecameNotVisible(
         std::move(worker_context_visibility_));
   }
 }
 
 }  // namespace cc