Implement pointer lock API for out-of-process iframes.

content/browser/frame_host/cross_process_frame_connector.cc

Index: content/browser/frame_host/cross_process_frame_connector.cc
diff --git a/content/browser/frame_host/cross_process_frame_connector.cc b/content/browser/frame_host/cross_process_frame_connector.cc
index f16ce70104142bdb79b0851987aef05f084ca063..4ab5a9f6c98380e7f674f3cb778cea3dcb2fa13d 100644
--- a/content/browser/frame_host/cross_process_frame_connector.cc
+++ b/content/browser/frame_host/cross_process_frame_connector.cc
@@ -191,6 +191,13 @@ void CrossProcessFrameConnector::FocusRootView() {
     root_view->Focus();
 }
 
+bool CrossProcessFrameConnector::LockMouse() {
+  RenderWidgetHostViewBase* root_view = GetRootRenderWidgetHostView();
+  if (root_view)
+    return root_view->LockMouse();
+  return false;
+}
+
 void CrossProcessFrameConnector::OnForwardInputEvent(
     const blink::WebInputEvent* event) {
   if (!view_)