Touch event flag should control only DOM event firing.

content/browser/renderer_host/render_view_host_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/browser/renderer_host/render_view_host_impl.h"
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 68 matching lines @@
 #include "content/public/common/file_chooser_file_info.h"
 #include "content/public/common/file_chooser_params.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/common/url_utils.h"
 #include "net/base/url_util.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/touch/touch_device.h"
-#include "ui/base/touch/touch_enabled.h"
 #include "ui/base/ui_base_switches.h"
+#include "ui/events/event_switches.h"
 #include "ui/gfx/animation/animation.h"
 #include "ui/gfx/color_space.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/native_theme/native_theme_switches.h"
 #include "url/url_constants.h"
 
 #if defined(OS_WIN)
 #include "ui/display/win/screen_win.h"
 #include "ui/gfx/geometry/dip_util.h"
@@ skipping 345 matching lines @@
   prefs.progress_bar_completion = GetProgressBarCompletionPolicy();
 
   prefs.use_solid_color_scrollbars = true;
 #endif
 
   // Handle autoplay gesture override experiment.
   // Note that anything but a well-formed string turns the experiment off.
   prefs.autoplay_experiment_mode = base::FieldTrialList::FindFullName(
       "MediaElementGestureOverrideExperiment");
 
-  prefs.touch_enabled = ui::AreTouchEventsEnabled();
-  prefs.device_supports_touch = prefs.touch_enabled &&
-      ui::GetTouchScreensAvailability() ==
-          ui::TouchScreensAvailability::ENABLED;
+  prefs.touch_event_api_enabled =
+      !(command_line.HasSwitch(switches::kTouchEvents) &&
+        command_line.GetSwitchValueASCII(switches::kTouchEvents) ==
+            switches::kTouchEventsDisabled);

[dcheng, 2016/11/17 11:25:11]

I'm a bit confused why the pref is called "enabled", but the RHS checks equality
of the switch value with "disabled".

[mustaq, 2016/11/17 13:44:30]

I also got a bit confused about it on my first reading, it was not obvious to me
that the NOT is for the whole RHS.

May be replacing
  !(A && B)
with
  !A || !B
makes it cleaner?

+  prefs.device_supports_touch = ui::GetTouchScreensAvailability() ==
+                                ui::TouchScreensAvailability::ENABLED;
   std::tie(prefs.available_pointer_types, prefs.available_hover_types) =
       ui::GetAvailablePointerAndHoverTypes();
   prefs.primary_pointer_type =
       ui::GetPrimaryPointerType(prefs.available_pointer_types);
   prefs.primary_hover_type =
       ui::GetPrimaryHoverType(prefs.available_hover_types);
 
 #if defined(OS_ANDROID)
   prefs.device_supports_mouse = false;
 #endif
@@ skipping 627 matching lines @@
   } else {
     render_view_ready_on_process_launch_ = true;
   }
 }
 
 void RenderViewHostImpl::RenderViewReady() {
   delegate_->RenderViewReady(this);
 }
 
 }  // namespace content