Fix crashes loading internal chrome pages powered by Mojo

chrome/browser/chrome_content_browser_manifest_overlay.json

Index: chrome/browser/chrome_content_browser_manifest_overlay.json
diff --git a/chrome/browser/chrome_content_browser_manifest_overlay.json b/chrome/browser/chrome_content_browser_manifest_overlay.json
index 9ad5febc9c40e24cdf4a35173b85af9270607b8e..6a2eda5ce600176aebfefe0fb9aa30b27caac88e 100644
--- a/chrome/browser/chrome_content_browser_manifest_overlay.json
+++ b/chrome/browser/chrome_content_browser_manifest_overlay.json
@@ -48,7 +48,13 @@
           "media_router::mojom::MediaRouter",
           "mojom::OmniboxPageHandler",
           "password_manager::mojom::CredentialManager",
-          "translate::mojom::ContentTranslateDriver"
+          "translate::mojom::ContentTranslateDriver",
+
+          // TODO(beng): These should be moved to a separate capability.

[Tom Sepez, 2016/10/31 21:45:05]

nit: Strictly speaking, Comments aren't allowed in JSON :(.  See www.json.org.

+          "mojom::OmniboxPageHandler",

[Will Harris, 2016/10/31 21:54:08]

how do we know that we have all the interfaces listed and none are missing?

+          "mojom::PluginsPageHandler",
+          "mojom::SiteEngagementUIHandler",
+          "mojom::UsbInternalsPageHandler"
         ]
       }
     }