Tiimer based phase info generated for mouse wheel events.

content/browser/renderer_host/render_widget_host_view_base.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_widget_host_view_base.h"
 
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
 #include "content/browser/renderer_host/input/synthetic_gesture_target_base.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_delegate.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_base_observer.h"
 #include "content/browser/renderer_host/render_widget_host_view_frame_subscriber.h"
 #include "content/browser/renderer_host/text_input_manager.h"
 #include "content/common/content_switches_internal.h"
+#include "content/public/common/content_features.h"
 #include "media/base/video_frame.h"
 #include "ui/base/layout.h"
 #include "ui/display/screen.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/size_f.h"
 
 namespace content {
 
 namespace {
 
 // How many microseconds apart input events should be flushed.
 const int kFlushInputRateInUs = 16666;
 
 }
 
 RenderWidgetHostViewBase::RenderWidgetHostViewBase()
     : is_fullscreen_(false),
       popup_type_(blink::kWebPopupTypeNone),
       mouse_locked_(false),
       showing_context_menu_(false),
       current_device_scale_factor_(0),
       current_display_rotation_(display::Display::ROTATE_0),
       text_input_manager_(nullptr),
+      wheel_scroll_latching_enabled_(base::FeatureList::IsEnabled(

[bokan, 2017/05/18 16:47:00]

Why do we need to store this? Can we just query FeatureList when you need it - I
think that should be cheap?

[sahel, 2017/05/18 18:15:14]

This way we need to include the content_features.h only here and use the getter
for wheel_scroll_latching_enabled_ variable in
render_widget_host_view_event_handler.cc (two places) and
render_widget_host_view_mac.mm (two places). I can change it to direct query if
you prefer not having a new variable here.

+          features::kTouchpadAndWheelScrollLatching)),
       renderer_frame_number_(0),
       weak_factory_(this) {}
 
 RenderWidgetHostViewBase::~RenderWidgetHostViewBase() {
   DCHECK(!mouse_locked_);
   // We call this here to guarantee that observers are notified before we go
   // away. However, some subclasses may wish to call this earlier in their
   // shutdown process, e.g. to force removal from
   // RenderWidgetHostInputEventRouter's surface map before relinquishing a
   // host pointer, as in RenderWidgetHostViewGuest. There is no harm in calling
@@ skipping 450 matching lines @@
 
 bool RenderWidgetHostViewBase::IsChildFrameForTesting() const {
   return false;
 }
 
 cc::SurfaceId RenderWidgetHostViewBase::SurfaceIdForTesting() const {
   return cc::SurfaceId();
 }
 
 }  // namespace content