Clean up stale references to scroll latching flags

The flags were removed in
https://chromium.googlesource.com/chromium/src/+/e6d81f47c871e49bb60ab45804dcb11e7c801667

Bug: 859171
Change-Id: I09b1d9e4b39e370da2efeb5ef076886cbe38296d
Reviewed-on: https://chromium-review.googlesource.com/c/1342657Reviewed-by: Sahel Sharify <sahel@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Kevin McNee <mcnee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610479}

testing/variations/fieldtrial_testing_config.json

@@ -5673,26 +5673,6 @@
             ]
         }
     ],
-    "WheelScrollLatchingAndAsyncWheelEvents": [
-        {
-            "platforms": [
-                "android",
-                "chromeos",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "AsyncWheelEvents",
-                        "TouchpadAndWheelScrollLatching"
-                    ]
-                }
-            ]
-        }
-    ],
     "WinOOPSelectFileDialog": [
         {
             "platforms": [

third_party/WebKit/LayoutTests/TestExpectations

@@ -1979,12 +1979,6 @@ crbug.com/779170 virtual/mouseevent_fractional/fast/events/constructors/mouse-ev
 crbug.com/779170 virtual/mouseevent_fractional/fast/events/constructors/wheel-event-constructor.html [ Failure ]
 crbug.com/779170 virtual/mouseevent_fractional/fast/events/zoom-dblclick.html [ Failure ]
 
-# These tests will pass once the --enable-features=TouchpadAndWheelScrollLatching flag is enabled by default.
-crbug.com/526463 fast/events/wheel/mouse-wheel-scroll-latching.html [ Pass Failure ]
-crbug.com/526463 fast/events/wheel/wheel-scroll-latching-on-scrollbar.html [ Pass Failure ]
-crbug.com/526463 virtual/mouseevent_fractional/fast/events/wheel/mouse-wheel-scroll-latching.html [ Pass Failure ]
-crbug.com/526463 virtual/mouseevent_fractional/fast/events/wheel/wheel-scroll-latching-on-scrollbar.html [ Pass Failure ]
-
 crbug.com/892032 fast/events/wheel/wheel-latched-scroll-node-removed.html [ Pass Failure ]
 crbug.com/892032 virtual/mouseevent_fractional/fast/events/wheel/wheel-latched-scroll-node-removed.html [ Pass Failure ]
 crbug.com/892032 virtual/user-activation-v2/fast/events/wheel/wheel-latched-scroll-node-removed.html [ Pass Failure ]

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1224,12 +1224,6 @@
       origin_trial_feature_name: "ForceTouchEventFeatureDetectionForInspector",
       status: "stable",
     },
-    // This is set conditionally in SetRuntimeFeaturesDefaultsAndUpdateFromArgs
-    // and will eventually go away when the touchpad/wheel scroll latching is
-    // enabled on all platforms (http://crbug.com/526463).
-    {
-      name: "TouchpadAndWheelScrollLatching",
-    },
     // When enabled, tracks the number of times each LayoutBlock
     // goes through layout. For testing purposes only.
     {