Forward MIME types to BrowserPlugin when a viewer is specified.

chrome/browser/chrome_content_browser_client.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/chrome_content_browser_client.h"
 
 #include <set>
 #include <utility>
 #include <vector>
 
@@ skipping 822 matching lines @@
   if (!service) {
     NOTREACHED();
     return;
   }
 
   /// TODO(fsamuel): In the future, certain types of GuestViewBases won't
   // require extension bindings. At that point, we should clear |extension_id|
   // instead of exiting early.
   if (!extension_id.empty() &&
       !service->GetExtensionById(extension_id, false)) {
-    NOTREACHED();
+    *guest_delegate =
+        GuestViewBase::Create(guest_instance_id,
+                              guest_web_contents,
+                              extension_id,
+                              "webview");
     return;
   }
 
   if (opener_web_contents) {
     GuestViewBase* guest = GuestViewBase::FromWebContents(opener_web_contents);
     if (!guest) {
       NOTREACHED();
       return;
     }
 
@@ skipping 1903 matching lines @@
       switches::kDisableWebRtcEncryption,
     };
     to_command_line->CopySwitchesFrom(from_command_line,
                                       kWebRtcDevSwitchNames,
                                       arraysize(kWebRtcDevSwitchNames));
   }
 }
 #endif  // defined(ENABLE_WEBRTC)
 
 }  // namespace chrome