Fix movementX/Y attributes for touch pointer events

content/browser/renderer_host/render_widget_host_view_base.h

Index: content/browser/renderer_host/render_widget_host_view_base.h
diff --git a/content/browser/renderer_host/render_widget_host_view_base.h b/content/browser/renderer_host/render_widget_host_view_base.h
index b7e0cda7766034cfe42ee7698329d66fe6aefed0..8d93b66d9dd4b0572943457f8d8b321c2eae7e23 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -108,6 +108,9 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   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;
@@ -482,6 +485,9 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
 
   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);