Add runtime setting to force passive event listeners.

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 
@@ skipping 710 matching lines @@
 
   WebSettings::SelectionStrategyType selection_strategy =
       WebSettings::SelectionStrategyType::Character;
   const std::string selection_strategy_str =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kTouchTextSelectionStrategy);
   if (selection_strategy_str == "direction")
     selection_strategy = WebSettings::SelectionStrategyType::Direction;
   webview()->settings()->setSelectionStrategy(selection_strategy);
 
+  std::string passiveListenersDefault =
+      command_line.GetSwitchValueASCII(switches::kPassiveListenersDefault);
+  if (!passiveListenersDefault.empty()) {
+    WebSettings::PassiveEventListenerDefault passiveDefault =
+        WebSettings::PassiveEventListenerDefault::False;
+    if (passiveListenersDefault == "documentonlytrue")
+      passiveDefault = WebSettings::PassiveEventListenerDefault::DocumentTrue;
+    else if (passiveListenersDefault == "true")
+      passiveDefault = WebSettings::PassiveEventListenerDefault::True;
+    else if (passiveListenersDefault == "forcealltrue")
+      passiveDefault = WebSettings::PassiveEventListenerDefault::ForceAllTrue;
+    webview()->settings()->setPassiveEventListenerDefault(passiveDefault);
+  }
+
   ApplyBlinkSettings(command_line, webview()->settings());
 
   if (params.main_frame_routing_id != MSG_ROUTING_NONE) {
     main_render_frame_ = RenderFrameImpl::CreateMainFrame(
         this, params.main_frame_routing_id, params.main_frame_widget_routing_id,
         params.hidden, screen_info(), compositor_deps_, opener_frame);
   }
 
   if (params.proxy_routing_id != MSG_ROUTING_NONE) {
     CHECK(params.swapped_out);
@@ skipping 2709 matching lines @@
   if (IsUseZoomForDSFEnabled()) {
     webview()->setZoomFactorForDeviceScaleFactor(device_scale_factor_);
   } else {
     webview()->setDeviceScaleFactor(device_scale_factor_);
   }
   webview()->settings()->setPreferCompositingToLCDTextEnabled(
       PreferCompositingToLCDText(compositor_deps_, device_scale_factor_));
 }
 
 }  // namespace content