GTK Render Widget Host View resets cached center location on mouse lock.

content/browser/renderer_host/render_widget_host_view_gtk.cc

Index: content/browser/renderer_host/render_widget_host_view_gtk.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_gtk.cc b/content/browser/renderer_host/render_widget_host_view_gtk.cc
index 852ed79dee4d9231c733d43fa1a0b0c096e92d3a..7c26122138a7d554d717a6712574ac2e4cce3586 100644
--- a/content/browser/renderer_host/render_widget_host_view_gtk.cc
+++ b/content/browser/renderer_host/render_widget_host_view_gtk.cc
@@ -207,8 +207,7 @@ class RenderWidgetHostViewGtkWidget {
   static gboolean OnConfigureEvent(GtkWidget* widget,
                                    GdkEventConfigure* event,
                                    RenderWidgetHostViewGtk* host_view) {
-    host_view->widget_center_valid_ = false;
-    host_view->mouse_has_been_warped_to_new_center_ = false;
+    host_view->MarkCachedWidgetCenterStale();
     return FALSE;
   }
 
@@ -1288,6 +1287,11 @@ bool RenderWidgetHostViewGtk::LockMouse() {
   // Clear the tooltip window.
   SetTooltipText(string16());
 
+  // Ensure that the widget center location will be relevant for this mouse
+  // lock session. It is updated whenever the window geometry moves
+  // but may be out of date due to switching tabs.
+  MarkCachedWidgetCenterStale();
+
   return true;
 }
 
@@ -1365,6 +1369,11 @@ void RenderWidgetHostViewGtk::set_last_mouse_down(GdkEventButton* event) {
   last_mouse_down_ = temp;
 }
 
+void RenderWidgetHostViewGtk::MarkCachedWidgetCenterStale() {
+  widget_center_valid_ = false;
+  mouse_has_been_warped_to_new_center_ = false;
+}
+
 gfx::Point RenderWidgetHostViewGtk::GetWidgetCenter() {
   if (widget_center_valid_)
     return widget_center_;