Reland FlingSchedulerMac for Viz

This relands the following change:

Enable FlingSchedulerMac

Enable tests that were disabled because of this functionality missing.

Bug: 842325
Change-Id: I6f540460f4e5f81d7ff8dd36e4abf369f0bd4785
Reviewed-on: https://chromium-review.googlesource.com/1149612Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577957}

This was identified as a cause of flakiness in Mac webkit_layout_tests. But that
test's flakiness also pre-dated this patch. The test in question has also been
marked to expect fails on Mac. The source of that flakiness will be investigated
separately.

Change-Id: I22364cb8e18507b528c6c0c32f452fcf208caf7e
Reviewed-on: https://chromium-review.googlesource.com/1162716
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581309}

content/browser/renderer_host/browser_compositor_view_mac.h

@@ -148,7 +148,7 @@ class CONTENT_EXPORT BrowserCompositorMac : public DelegatedFrameHostClient,
 
   bool ForceNewSurfaceForTesting();
 
-  ui::Compositor* GetCompositorForTesting() const;
+  ui::Compositor* GetCompositor() const;
 
  private:
   // ui::LayerObserver implementation:

content/browser/renderer_host/browser_compositor_view_mac.mm

@@ -496,7 +496,9 @@ void BrowserCompositorMac::LayerDestroyed(ui::Layer* layer) {
   SetParentUiLayer(nullptr);
 }
 
-ui::Compositor* BrowserCompositorMac::GetCompositorForTesting() const {
+ui::Compositor* BrowserCompositorMac::GetCompositor() const {
+  if (parent_ui_layer_)
+    return parent_ui_layer_->GetCompositor();
   if (recyclable_compositor_)
     return recyclable_compositor_->compositor();
   return nullptr;

content/browser/renderer_host/input/fling_browsertest.cc

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/viz/common/features.h"
 #include "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/test/browser_test_utils.h"
@@ -84,13 +83,6 @@ class BrowserSideFlingBrowserTest : public ContentBrowserTest {
 };
 
 IN_PROC_BROWSER_TEST_F(BrowserSideFlingBrowserTest, TouchscreenFling) {
-#if defined(OS_MACOSX)
-  // TODO(jonross): Re-enable once fling on Mac works with Viz.
-  // https://crbug.com/842325
-  if (base::FeatureList::IsEnabled(features::kVizDisplayCompositor))
-    return;
-#endif  // defined(OS_MACOSX)
-
   LoadURL(kBrowserFlingDataURL);
 
   // Send a GSB to start scrolling sequence.
@@ -124,13 +116,6 @@ IN_PROC_BROWSER_TEST_F(BrowserSideFlingBrowserTest, TouchscreenFling) {
 }
 
 IN_PROC_BROWSER_TEST_F(BrowserSideFlingBrowserTest, TouchpadFling) {
-#if defined(OS_MACOSX)
-  // TODO(jonross): Re-enable once fling on Mac works with Viz.
-  // https://crbug.com/842325
-  if (base::FeatureList::IsEnabled(features::kVizDisplayCompositor))
-    return;
-#endif  // defined(OS_MACOSX)
-
   LoadURL(kBrowserFlingDataURL);
 
   // Send a wheel event to start scrolling sequence.

content/browser/renderer_host/input/fling_scheduler_mac.mm

@@ -21,14 +21,10 @@ ui::Compositor* FlingSchedulerMac::GetCompositor() {
   // RWHV_child_frame doesn't have DelegatedFrameHost with ui::Compositor.
   if (host_->GetView()->IsRenderWidgetHostViewChildFrame())
     return nullptr;
-
-  // TODO(sahel): Uncomment this once Viz is ready on Mac.
-  // https://crbug.com/833985
-  /* RenderWidgetHostViewMac* view =
+  RenderWidgetHostViewMac* view =
       static_cast<RenderWidgetHostViewMac*>(host_->GetView());
   if (view->BrowserCompositor())
-    return view->BrowserCompositor()->Compositor();
-  } */
+    return view->BrowserCompositor()->GetCompositor();
 
   return nullptr;
 }

content/browser/renderer_host/render_widget_host_view_mac_unittest.mm

@@ -1957,11 +1957,11 @@ TEST_F(InputMethodMacTest, MonitorCompositionRangeForActiveWidget) {
 
 TEST_F(RenderWidgetHostViewMacTest, ClearCompositorFrame) {
   BrowserCompositorMac* browser_compositor = rwhv_mac_->BrowserCompositor();
-  ui::Compositor* ui_compositor = browser_compositor->GetCompositorForTesting();
+  ui::Compositor* ui_compositor = browser_compositor->GetCompositor();
   EXPECT_NE(ui_compositor, nullptr);
   EXPECT_TRUE(ui_compositor->IsLocked());
   rwhv_mac_->ClearCompositorFrame();
-  EXPECT_EQ(browser_compositor->GetCompositorForTesting(), ui_compositor);
+  EXPECT_EQ(browser_compositor->GetCompositor(), ui_compositor);
   EXPECT_FALSE(ui_compositor->IsLocked());
 }
 

third_party/WebKit/LayoutTests/TestExpectations

@@ -4860,3 +4860,8 @@ crbug.com/871578 [ Mac ] virtual/outofblink-cors-ns/external/wpt/xhr/timeout-mul
 crbug.com/869470 external/wpt/background-fetch/fetch.https.window.html [ Pass Failure ]
 crbug.com/869470 external/wpt/background-fetch/get.https.window.html [ Pass Failure ]
 crbug.com/869470 external/wpt/background-fetch/get-ids.https.window.html [ Pass Failure ]
+
+# Flaky middleClinkAutoscroll increased flakiness on Mac
+crbug.com/851090 [ Mac ] fast/events/middleClickAutoscroll-click-hyperlink.html [ Failure Pass ]
+crbug.com/851090 [ Mac ] virtual/mouseevent_fractional/fast/events/middleClickAutoscroll-nested-divs.html [ Failure Pass ]
+crbug.com/851090 [ Mac ] virtual/user-activation-v2/fast/events/autoscroll-over-scrollbar.html [ Failure Pass ]