Reland "Disable wheel scroll latching in failing content_browsertests."

This reverts commit 431c6dbf.

Reason for revert: r543765 caused more test failures, tracked in https://crbug.com/822980.

Original change's description:
> Revert "Disable wheel scroll latching in failing content_browsertests."
> 
> This reverts commit f2bf009a.
> 
> Reason for revert: There has been a few bug fixes related to oopif and
> latching, I will enable the latching flag to see if the failing tests
> are fixed or not. If not I will disable the tests again addressing crbug.com/822764 bug as well.
> 
> Original change's description:
> > Disable wheel scroll latching in failing content_browsertests.
> > 
> > I cannot reproduce the test failures on my local official windows build,
> > in this cl I force wheel scroll latching to be disabled in the tests to
> > see if it changes the test results on Win official or not.
> > 
> > Bug: 800822
> > Change-Id: Ife07a29617ca5e0142e75f926967685cb61e2a08
> > Reviewed-on: https://chromium-review.googlesource.com/895842
> > Reviewed-by: James MacLean <wjmaclean@chromium.org>
> > Reviewed-by: Nasko Oskov <nasko@chromium.org>
> > Commit-Queue: Sahel Sharifymoghaddam <sahel@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#533347}
> 
> TBR=nasko@chromium.org,wjmaclean@chromium.org,sahel@chromium.org
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Bug: 800822, 822764
> Change-Id: I563672dfbcb01298324a2b884cbed0e69c220339
> Reviewed-on: https://chromium-review.googlesource.com/966687
> Reviewed-by: Sahel Sharifymoghaddam <sahel@chromium.org>
> Commit-Queue: Sahel Sharifymoghaddam <sahel@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#543765}

TBR=nasko@chromium.org,wjmaclean@chromium.org,sahel@chromium.org

Change-Id: Ie0212e01b308826c96eac54b86168ce9d1d04231
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 800822, 822764
Reviewed-on: https://chromium-review.googlesource.com/967522Reviewed-by: Charlie Reis <creis@chromium.org>
Commit-Queue: Charlie Reis <creis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543883}

content/browser/site_per_process_hit_test_browsertest.cc

@@ -10,6 +10,7 @@
 #include "base/feature_list.h"
 #include "base/json/json_reader.h"
 #include "base/test/bind_test_util.h"
+#include "base/test/scoped_feature_list.h"
 #include "base/test/test_timeouts.h"
 #include "build/build_config.h"
 #include "components/viz/common/features.h"
@@ -1878,12 +1879,17 @@ class SitePerProcessMouseWheelHitTestBrowserTest
     EXPECT_EQ("\"scroll: 3\"", reply);
   }
 
+ protected:
+  base::test::ScopedFeatureList feature_list_;
+
  private:
   RenderWidgetHostViewAura* rwhv_root_;
 };
 
 IN_PROC_BROWSER_TEST_P(SitePerProcessMouseWheelHitTestBrowserTest,
                        SubframeWheelEventsOnMainThread) {
+  feature_list_.InitWithFeatures({}, {features::kTouchpadAndWheelScrollLatching,
+                                      features::kAsyncWheelEvents});
   GURL main_url(embedded_test_server()->GetURL(
       "/frame_tree/page_with_positioned_nested_frames.html"));
   EXPECT_TRUE(NavigateToURL(shell(), main_url));
@@ -1899,6 +1905,8 @@ IN_PROC_BROWSER_TEST_P(SitePerProcessMouseWheelHitTestBrowserTest,
   // surface information required for event hit testing is ready.
   RenderWidgetHostViewBase* child_rwhv = static_cast<RenderWidgetHostViewBase*>(
       root->child_at(0)->current_frame_host()->GetView());
+
+  EXPECT_FALSE(child_rwhv->wheel_scroll_latching_enabled());
   WaitForChildFrameSurfaceReady(root->child_at(0)->current_frame_host());
 
   content::RenderFrameHostImpl* child = root->child_at(0)->current_frame_host();
@@ -1914,6 +1922,8 @@ IN_PROC_BROWSER_TEST_P(SitePerProcessMouseWheelHitTestBrowserTest,
 // the same page loaded in the mainframe.
 IN_PROC_BROWSER_TEST_P(SitePerProcessMouseWheelHitTestBrowserTest,
                        MainframeWheelEventsOnMainThread) {
+  feature_list_.InitWithFeatures({}, {features::kTouchpadAndWheelScrollLatching,
+                                      features::kAsyncWheelEvents});
   GURL main_url(
       embedded_test_server()->GetURL("/page_with_scrollable_div.html"));
   EXPECT_TRUE(NavigateToURL(shell(), main_url));
@@ -1922,6 +1932,9 @@ IN_PROC_BROWSER_TEST_P(SitePerProcessMouseWheelHitTestBrowserTest,
   content::RenderFrameHostImpl* rfhi = root->current_frame_host();
   SetupWheelAndScrollHandlers(rfhi);
 
+  EXPECT_FALSE(
+      rfhi->GetRenderWidgetHost()->GetView()->wheel_scroll_latching_enabled());
+
   gfx::Point pos(10, 10);
 
   RunTest(pos, rfhi->GetRenderWidgetHost()->GetView());