Perform direct routing of mouse events when the pointer is locked.

content/browser/renderer_host/render_widget_host_input_event_router.cc

Index: content/browser/renderer_host/render_widget_host_input_event_router.cc
diff --git a/content/browser/renderer_host/render_widget_host_input_event_router.cc b/content/browser/renderer_host/render_widget_host_input_event_router.cc
index f036a77d159f402315ad746322ed15109205bfea..0c9db9f5f2f72bd1da321533136c96573d9aabb8 100644
--- a/content/browser/renderer_host/render_widget_host_input_event_router.cc
+++ b/content/browser/renderer_host/render_widget_host_input_event_router.cc
@@ -173,6 +173,15 @@ void RenderWidgetHostInputEventRouter::RouteMouseEvent(
     RenderWidgetHostViewBase* root_view,
     blink::WebMouseEvent* event,
     const ui::LatencyInfo& latency) {
+  if (root_view->IsMouseLocked()) {

[kenrb, 2016/12/22 15:14:16]

You need to transform the event's coordinates into the widget's coordinate
space. Also, do you need to null check the return of GetView(), to guard against
a race with a process crash? I gave it a quick look, and don't see a way that
the lock would get immediately released after RWHVCF::RenderProcessGone.

[lfg, 2017/02/13 20:16:07]

Done. I don't think we need to null check GetView(), since
WebContentsImpl::RenderWidgetDeleted releases the mouse lock when a widget dies.

[kenrb, 2017/02/14 19:58:49]

I don't think child frame RWHImpls necessarily get destroyed when their process
crashes. Only their views do.

[lfg, 2017/02/15 20:12:03]

After further investigation, this isn't necessary. The mouse is unlocked when
the process is destroyed, it happens in the destructors of
RenderWidgetHostViewAura, RenderWidgetHostViewMac and in
RenderWidgetHostViewChildFrame::SetCrossProcessFrameConnector, called from
RenderWidgetHostViewChildFrame::Destroy.

We should never get to this point without an existing view.

+    RenderWidgetHostImpl::From(root_view->GetRenderWidgetHost())
+        ->delegate()
+        ->MouseLockWidget()
+        ->GetView()
+        ->ProcessMouseEvent(*event, latency);
+    return;
+  }
+
   RenderWidgetHostViewBase* target;
   gfx::Point transformed_point;
   const int mouse_button_modifiers = blink::WebInputEvent::LeftButtonDown |
@@ -247,6 +256,15 @@ void RenderWidgetHostInputEventRouter::RouteMouseWheelEvent(
     RenderWidgetHostViewBase* root_view,
     blink::WebMouseWheelEvent* event,
     const ui::LatencyInfo& latency) {
+  if (root_view->IsMouseLocked()) {

[kenrb, 2016/12/22 15:14:16]

Likewise for the transform.

[lfg, 2017/02/13 20:16:07]

Done.

+    RenderWidgetHostImpl::From(root_view->GetRenderWidgetHost())
+        ->delegate()
+        ->MouseLockWidget()
+        ->GetView()
+        ->ProcessMouseEvent(*event, latency);
+    return;
+  }
+
   gfx::Point transformed_point;
   RenderWidgetHostViewBase* target = FindEventTarget(
       root_view, gfx::Point(event->x, event->y), &transformed_point);