Pointer/hover media query support: platform-dependent changes

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 404 matching lines @@
   const std::string autoplay_group_name = base::FieldTrialList::FindFullName(
       "MediaElementAutoplay");
   prefs.user_gesture_required_for_media_playback = !command_line.HasSwitch(
       switches::kDisableGestureRequirementForMediaPlayback) &&
           (autoplay_group_name.empty() || autoplay_group_name != "Enabled");
 #endif
 
   prefs.touch_enabled = ui::AreTouchEventsEnabled();
   prefs.device_supports_touch = prefs.touch_enabled &&
       ui::IsTouchDevicePresent();
+  prefs.available_pointer_types = ui::AvailablePointerTypes();
+  prefs.primary_pointer_type = ui::PrimaryPointerType();
+  prefs.available_hover_types = ui::AvailableHoverTypes();
+  prefs.primary_hover_type = ui::PrimaryHoverType();
+
 #if defined(OS_ANDROID)
   prefs.device_supports_mouse = false;
 #endif
 
   prefs.pointer_events_max_touch_points = ui::MaxTouchPoints();
 
   prefs.touch_adjustment_enabled =
       !command_line.HasSwitch(switches::kDisableTouchAdjustment);
 
   prefs.slimming_paint_enabled =
@@ skipping 901 matching lines @@
   OnToggleFullscreen(false);
 }
 
 WebPreferences RenderViewHostImpl::GetWebkitPreferences() {
   if (!web_preferences_.get()) {
     OnWebkitPreferencesChanged();
   }
   return *web_preferences_;
 }
 
 void RenderViewHostImpl::UpdateWebkitPreferences(const WebPreferences& prefs) {

[jdduke (slow), 2014/11/26 19:29:28]

Any idea how frequently this gets called?

[mustaq, 2014/11/26 19:51:50]

It seems RenderViewHostImpl::CreateRenderView is the only "end"-user for this.
So it gets called only during browser startup I think. Or may be new tab.

Rick, you mentioned about supporting hot-plugging of input devices though this
method, right?

[jdduke (slow), 2014/11/26 20:05:38]

I ask because each of the queries into Java are likely generating garbage, so as
long as they're called relatively infrequently, I'm happy. Note that there's
also an |InputDeviceListener| interface
(http://developer.android.com/reference/android/hardware/input/InputManager.In...)
if we wanted to push these values when we detect a change in hover/pointer
types.

[mustaq, 2014/12/02 16:28:19]

Acknowledged.

[mustaq, 2014/12/02 21:50:02]

Here is a better answer to your original question: it is called once per page
load. Just double-checked by running on linux and Android.

   web_preferences_.reset(new WebPreferences(prefs));
   Send(new ViewMsg_UpdateWebPreferences(GetRoutingID(), prefs));
 }
 
 void RenderViewHostImpl::OnWebkitPreferencesChanged() {
   // This is defensive code to avoid infinite loops due to code run inside
   // UpdateWebkitPreferences() accidentally updating more preferences and thus
   // calling back into this code. See crbug.com/398751 for one past example.
   if (updating_web_preferences_)
     return;
@@ skipping 111 matching lines @@
   FrameTree* frame_tree = delegate_->GetFrameTree();
 
   frame_tree->ResetForMainFrameSwap();
 }
 
 void RenderViewHostImpl::SelectWordAroundCaret() {
   Send(new ViewMsg_SelectWordAroundCaret(GetRoutingID()));
 }
 
 }  // namespace content