Force events to be non blocking if main thread is unresponsive.

content/public/common/content_features.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 #include "content/public/common/content_features.h"
 
 namespace features {
 
 // All features in alphabetical order.
@@ skipping 80 matching lines @@
 };
 
 // Enables the memory coordinator.
 // WARNING:
 // The memory coordinator is not ready for use and enabling this may cause
 // unexpected memory regression at this point. Please do not enable this.
 const base::Feature kMemoryCoordinator {
   "MemoryCoordinator", base::FEATURE_DISABLED_BY_DEFAULT
 };
 
+// An experiment forcing events to be non-blocking when the main thread is
+// deemed unresponsive.  See crbug.com/599609.
+const base::Feature kMainThreadBusyScrollIntervention{
+    "MainThreadBusyScrollIntervention", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Non-validating reload for desktop.
 // See https://crbug.com/591245
 const base::Feature kNonValidatingReloadOnNormalReload{
     "NonValidatingReloadOnNormalReload", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // An experiment to optimize resource loading IPC for small resources.
 // http://crbug.com/580928
 const base::Feature kOptimizeLoadingIPCForSmallResources{
     "OptimizeLoadingIPCForSmallResources",
     base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Origin Trials for controlling access to feature/API experiments.
 const base::Feature kOriginTrials{"OriginTrials",
                                   base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Whether the lookahead parser in Blink runs on the main thread.
 const base::Feature kParseHTMLOnMainThread{"ParseHTMLOnMainThread",
                                            base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Whether document level event listeners should default 'passive' to true.
 const base::Feature kPassiveDocumentEventListeners{
     "PassiveDocumentEventListeners", base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Whether we should force a touchstart and first touchmove per scroll event
-// listeners to be 'passive' during fling.
+// listeners to be non-blocking during fling.
 const base::Feature kPassiveEventListenersDueToFling{
     "PassiveEventListenersDueToFling", base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Pointer events support.
 const base::Feature kPointerEvents{"PointerEvent",
                                    base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Whether pointer event capturing follow v1 spec instead of v2 proposal.
 // See https://rawgit.com/w3c/pointerevents/reduce-hit-tests/index.html.
 const base::Feature kPointerEventV1SpecCapturing{
@@ skipping 103 matching lines @@
 #endif
 
 #if defined(OS_WIN)
 // Emergency "off switch" for new Windows sandbox security mitigation,
 // sandbox::MITIGATION_EXTENSION_POINT_DISABLE.
 const base::Feature kWinSboxDisableExtensionPoints{
     "WinSboxDisableExtensionPoint", base::FEATURE_ENABLED_BY_DEFAULT};
 #endif
 
 }  // namespace features