Implement pointer lock across outer/inner WebContents.

extensions/browser/guest_view/web_view/web_view_guest.cc

Index: extensions/browser/guest_view/web_view/web_view_guest.cc
diff --git a/extensions/browser/guest_view/web_view/web_view_guest.cc b/extensions/browser/guest_view/web_view/web_view_guest.cc
index 4276b3c9af6e79f98dbc8a99223c0b5b795a0ea8..6bcb5b8c8f3b2c55d812b22ade2a4136e9ad578d 100644
--- a/extensions/browser/guest_view/web_view/web_view_guest.cc
+++ b/extensions/browser/guest_view/web_view/web_view_guest.cc
@@ -1375,6 +1375,18 @@ bool WebViewGuest::IsFullscreenForTabOrPending(
   return is_guest_fullscreen_;
 }
 
+void WebViewGuest::RequestToLockMouse(WebContents* web_contents,
+                                      bool user_gesture,
+                                      bool last_unlocked_by_target) {
+  RequestPointerLockPermission(
+      user_gesture, last_unlocked_by_target,
+      base::Bind(
+          [](WebContents* web_contents, bool allowed) {

[ncarter (slow), 2016/12/22 00:01:07]

Why not:

base::Bind(base::IgnoreResult(&WebContents::GotResponseToLockMouseRequest),
base::Unretained(web_contents)); ?

I think dcheng had mentioned that lambdas w/ Bind are to be avoided if possible,
because we prefer the forms that make the caller use base::Unretained or some
other indication of pointer ownership semantics.

[lfg, 2016/12/22 19:23:55]

Oh, that's nice, I wasn't aware of base::IgnoreResult. Done.

+            web_contents->GotResponseToLockMouseRequest(allowed);
+          },
+          web_contents));
+}
+
 void WebViewGuest::LoadURLWithParams(
     const GURL& url,
     const content::Referrer& referrer,