If JavaScript shows a dialog, cause the page to lose fullscreen.

BUG=670135, 550017, 726761, 728276

Review-Url: https://codereview.chromium.org/2906133004
Cr-Commit-Position: refs/heads/master@{#478884}
void WebContentsImpl::WebContentsTreeNode::ConnectToOuterWebContents(
    WebContentsImpl* outer_web_contents,
    RenderFrameHostImpl* outer_contents_frame) {
  focused_web_contents_ = nullptr;
  outer_web_contents_ = outer_web_contents;
  outer_contents_frame_tree_node_id_ =
      outer_contents_frame->frame_tree_node()->frame_tree_node_id();

  outer_web_contents_->node_.AttachInnerWebContents(current_web_contents_);
  outer_contents_frame->frame_tree_node()->AddObserver(this);
}

void WebContentsImpl::WebContentsTreeNode::ConnectToOuterWebContents(
    WebContentsImpl* outer_web_contents,
    RenderFrameHostImpl* outer_contents_frame) {
  focused_web_contents_ = nullptr;
  outer_web_contents_ = outer_web_contents;
  outer_contents_frame_tree_node_id_ =
      outer_contents_frame->frame_tree_node()->frame_tree_node_id();

  outer_web_contents_->node_.AttachInnerWebContents(current_web_contents_);
  outer_contents_frame->frame_tree_node()->AddObserver(this);
}
