Remove unused BlinkSchedulerHighPriorityInputOnCompositorThread

Bug: 1053702
Change-Id: I65814fdd8ba45c46195141c5d5303bf49baf2c81
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2397996Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805947}

testing/variations/fieldtrial_testing_config.json

@@ -706,27 +706,6 @@
             ]
         }
     ],
-    "BlinkSchedulerHighPriorityInputOnCompositorThread": [
-        {
-            "platforms": [
-                "android",
-                "android_weblayer",
-                "chromeos",
-                "ios",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "BlinkSchedulerHighPriorityInputOnCompositorThread"
-                    ]
-                }
-            ]
-        }
-    ],
     "BlinkSchedulerPerAgentSchedulingStudy": [
         {
             "platforms": [

third_party/blink/renderer/platform/scheduler/common/features.h

@@ -13,10 +13,6 @@
 namespace blink {
 namespace scheduler {
 
-const base::Feature kHighPriorityInputOnCompositorThread{
-    "BlinkSchedulerHighPriorityInputOnCompositorThread",
-    base::FEATURE_DISABLED_BY_DEFAULT};
-
 const base::Feature kDedicatedWorkerThrottling{
     "BlinkSchedulerWorkerThrottling", base::FEATURE_DISABLED_BY_DEFAULT};