Fix movementX/Y attributes for touch pointer events

content/browser/renderer_host/render_widget_host_view_base.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 90 matching lines @@
   base::string16 GetSelectedText() override;
   bool IsMouseLocked() override;
   gfx::Size GetVisibleViewportSize() const override;
   void SetInsets(const gfx::Insets& insets) override;
   void BeginFrameSubscription(
       std::unique_ptr<RenderWidgetHostViewFrameSubscriber> subscriber) override;
   void EndFrameSubscription() override;
   void FocusedNodeTouched(const gfx::Point& location_dips_screen,
                           bool editable) override;
 
+  // Keeps track of last position of touch points and sets MovementXY for them.
+  void SetMovementXYForTouchPoints(blink::WebTouchEvent* event);
+
   // This only needs to be overridden by RenderWidgetHostViewBase subclasses
   // that handle content embedded within other RenderWidgetHostViews.
   gfx::Point TransformPointToRootCoordSpace(const gfx::Point& point) override;
   gfx::PointF TransformPointToRootCoordSpaceF(
       const gfx::PointF& point) override;
 
   // IPC::Listener implementation:
   bool OnMessageReceived(const IPC::Message& msg) override;
 
   void SetPopupType(blink::WebPopupType popup_type);
@@ skipping 354 matching lines @@
   void FlushInput();
 
   gfx::Rect current_display_area_;
 
   uint32_t renderer_frame_number_;
 
   base::OneShotTimer flush_input_timer_;
 
   base::ObserverList<RenderWidgetHostViewBaseObserver> observers_;
 
+  // Last touch position relative to screen. Used to compute movementX/Y.
+  std::map<int, gfx::Point> global_touch_position_;

[Rick Byers, 2017/02/06 22:00:53]

Is there a reason to put this here instead of in
RenderWidgetHostViewEventHandler where the corresponding fields for mouse
already are?  In general RenderWidgetHostViewBase is already pretty big, so the
more we can keep event-related-state / processing to
RenderWidgetHostViewEventHandler the cleaner IMHO.

[Navid Zolghadr, 2017/02/06 22:40:41]

I asked about this from jonross@. He mentioned RenderWidgetHostViewEventHandler
was created to abstract the logic of Aura to be used in mus later on. So those
two classes will share RenderWidgetHostViewEventHandler and not the Android one.
He also mentioned that the class doesn't seem to be necessary after some
discussions on how mus should integrate in. Anyhow RenderWidgetHostViewAndroid 
doesn't have any instance of RenderWidgetHostViewEventHandler. That is why I put
it in the main class.

[sadrul, 2017/02/07 03:48:30]

Can this live in InputRouterImpl instead? Ideally, each platform wouldn't have
to remember to explicitly update the fields. Putting this code in
InputRouterImpl will make sure the fields are updated correctly on all
platforms.

[Navid Zolghadr, 2017/02/07 15:43:05]

The reason I added it here is mostly because I wanted to keep it in (almost) the
same as setting movementX/Y properties for mouse which is done in
render_widget_host_view_event_handler.cc. Do you think that can also be moved to
InputRouterImpl then?

[Navid Zolghadr, 2017/02/08 17:18:49]

Done. I haven't moved the mouse one yet. But I'll keep that in mind to do it in
a later round of clean up when we add the mouse support to Android as well so
that logic would fully apply to all the platforms.
 

+
   base::WeakPtrFactory<RenderWidgetHostViewBase> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewBase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_