Make WebContents::GetOuterWebContents() const.

Change-Id: I60d5a327f7f0ad22dccdbdcbe15dbfaf89f98918
Reviewed-on: https://chromium-review.googlesource.com/c/1302493
Reviewed-by: Alex Moshchuk <[email protected]>
Commit-Queue: Lucas Gadani <[email protected]>
Cr-Commit-Position: refs/heads/master@{#603972}
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 7fc1ad54..fd677b0 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -5417,7 +5417,7 @@
     browser_plugin_embedder_.reset();
 }
 
-WebContentsImpl* WebContentsImpl::GetOuterWebContents() {
+WebContentsImpl* WebContentsImpl::GetOuterWebContents() const {
   if (GuestMode::IsCrossProcessFrameGuest(this))
     return node_.outer_web_contents();