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 cb96ee2baaebbe5c11a0de76ae583bf83fb0c90c..fc7120a3ae185cdaf51fa0d25437a1536e91adaf 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
@@ -175,6 +175,22 @@ void RenderWidgetHostInputEventRouter::RouteMouseEvent(
     const ui::LatencyInfo& latency) {
   RenderWidgetHostViewBase* target;

[Charlie Reis, 2017/02/15 21:38:49]

Given all the conditional assignments below, let's assign this to nullptr to
avoid any risk of uninitialized reads (e.g., after future refactors).

[lfg, 2017/02/15 22:02:48]

Done.

   gfx::Point transformed_point;
+
+  if (root_view->IsMouseLocked()) {

[Charlie Reis, 2017/02/15 21:38:49]

It's probably worth putting a comment on this block, given that it handles mouse
lock specially and then early returns.

[lfg, 2017/02/15 22:02:48]

Done.

+    target = RenderWidgetHostImpl::From(root_view->GetRenderWidgetHost())
+                 ->delegate()
+                 ->MouseLockWidget()
+                 ->GetView();
+    if (!root_view->TransformPointToCoordSpaceForView(
+            gfx::Point(event->x, event->y), target, &transformed_point))
+      return;
+
+    event->x = transformed_point.x();
+    event->y = transformed_point.y();
+    target->ProcessMouseEvent(*event, latency);
+    return;
+  }
+
   const int mouse_button_modifiers = blink::WebInputEvent::LeftButtonDown |
                                      blink::WebInputEvent::MiddleButtonDown |
                                      blink::WebInputEvent::RightButtonDown;
@@ -247,6 +263,15 @@ void RenderWidgetHostInputEventRouter::RouteMouseWheelEvent(
     RenderWidgetHostViewBase* root_view,
     blink::WebMouseWheelEvent* event,
     const ui::LatencyInfo& latency) {
+  if (root_view->IsMouseLocked()) {
+    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);