Force MimeHandlerView to always use BrowserPlugin

content/public/browser/guest_mode.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_PUBLIC_BROWSER_GUEST_MODE_H_
+#define CONTENT_PUBLIC_BROWSER_GUEST_MODE_H_
+
+#include "base/macros.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class WebContents;
+
+// TODO(ekaramad): This class is temporarily added to provide a workaround for
+// allowing the existence of some guests based on browser plugin rather than
+// cross process frames. It will be removed once the issue
+// https://crbug.com/642826 is resolved.

[Charlie Reis, 2016/09/23 05:21:26]

I think we can leave out this TODO.  Even when the PDF case supports OOPIFs,
we'll still need a policy function to control the Finch trial, and we might as
well keep this one (and the new one you've added in the renderer).

[EhsanK, 2016/09/23 14:53:22]

Acknowledged.

+class CONTENT_EXPORT GuestMode {
+ public:
+  // Returns true if |web_contents| is an inner WebContents based on cross
+  // process frames.
+  static bool IsCrossProcessFrameGuest(WebContents* web_contents);
+
+ private:
+  GuestMode();
+
+  DISALLOW_COPY_AND_ASSIGN(GuestMode);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_GUEST_MODE_H_