Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/public/browser/browser_plugin_guest_delegate.h

Index: content/public/browser/browser_plugin_guest_delegate.h
diff --git a/content/public/browser/browser_plugin_guest_delegate.h b/content/public/browser/browser_plugin_guest_delegate.h
index d689b944d456033842a014c5d120e4ef7d522072..39b045b14c56baea9255517225823a0ac7cdfc90 100644
--- a/content/public/browser/browser_plugin_guest_delegate.h
+++ b/content/public/browser/browser_plugin_guest_delegate.h
@@ -93,6 +93,15 @@ class CONTENT_EXPORT BrowserPluginGuestDelegate {
   // a BrowserPlugin even when we are using cross process frames for guests. It
   // should be removed after resolving https://crbug.com/642826).
   virtual bool CanUseCrossProcessFrames();
+
+  // Returns the RenderFrameHost corresponding to the RenderFrame embedding the
+  // BrowserPlugin. This is the main frame for the owner of the guests, unless
+  // the guest is embedded inside a cross origin frame.
+  virtual RenderFrameHost* GetOwnerFrame();
+
+  // Returns true if the corresponding guest is allowed to be embedded inside an
+  // <iframe> which is cross process.
+  virtual bool CanBeEmbeddedInsideCrossProcessFrames();
 };
 
 }  // namespace content