[ScrollUnification] Fix CompositedScrollingMetricTest failing tests

During ScrollUnification, scrolling was moved to the compositor
thread. CompositedScrollingMetricTest tests need to be updated to
reflect this so they pass when the ScrollUnification flag is on.

Bug: 1086625
Change-Id: Ib70f4830d8007463228f9dd9b1ac41318b4bada9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364055
Commit-Queue: Liviu Tinta <liviutinta@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800193}

content/browser/renderer_host/input/composited_scrolling_browsertest.cc

@@ -12,6 +12,7 @@
 #include "base/test/metrics/histogram_tester.h"
 #include "base/test/scoped_feature_list.h"
 #include "build/build_config.h"
+#include "cc/base/features.h"
 #include "content/browser/renderer_host/input/synthetic_gesture.h"
 #include "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
@@ -257,6 +258,12 @@ IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest,
 
   base::HistogramBase::Sample expected_bucket =
       CompositingEnabled() ? kScrollingOnCompositor : kScrollingOnMain;
+  if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
+    // TODO: crbug.com/1082590
+    // After ScrollUnification all scrolls happen on the compositor thread
+    // but some will still force blocking on main thread
+    expected_bucket = kScrollingOnCompositor;
+  }
 
   histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
   histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
@@ -304,6 +311,12 @@ IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest, BlockingEventHandlers) {
   base::HistogramBase::Sample expected_bucket =
       CompositingEnabled() ? kScrollingOnCompositorBlockedOnMain
                            : kScrollingOnMain;
+  if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
+    // TODO: crbug.com/1082590
+    // After ScrollUnification all scrolls happen on the compositor thread
+    // but some will still force blocking on main thread
+    expected_bucket = kScrollingOnCompositorBlockedOnMain;
+  }
 
   histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
   histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
@@ -351,6 +364,12 @@ IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest, PassiveEventHandlers) {
 
   base::HistogramBase::Sample expected_bucket =
       CompositingEnabled() ? kScrollingOnCompositor : kScrollingOnMain;
+  if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
+    // TODO: crbug.com/1082590
+    // After ScrollUnification all scrolls happen on the compositor thread
+    // but some will still force blocking on main thread
+    expected_bucket = kScrollingOnCompositor;
+  }
 
   histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
   histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);