Add delegate to install web_contents helpers for MimeHandlerView.

extensions/browser/api/extensions_api_client.h

Index: extensions/browser/api/extensions_api_client.h
diff --git a/extensions/browser/api/extensions_api_client.h b/extensions/browser/api/extensions_api_client.h
index 9332dc6cad12d112d5b8238208534ae1f802c10b..5cd3cee95e940b5be8fb5207422c6e8245ddcea1 100644
--- a/extensions/browser/api/extensions_api_client.h
+++ b/extensions/browser/api/extensions_api_client.h
@@ -8,6 +8,7 @@
 #include <map>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "extensions/browser/api/storage/settings_namespace.h"
 
 class GURL;
@@ -22,6 +23,8 @@ class BrowserContext;
 namespace extensions {
 
 class AppViewGuestDelegate;
+class MimeHandlerViewGuest;
+class MimeHandlerViewGuestDelegate;
 class WebViewGuest;
 class WebViewGuestDelegate;
 class WebViewPermissionHelper;
@@ -57,6 +60,10 @@ class ExtensionsAPIClient {
   // Creates the AppViewGuestDelegate.
   virtual AppViewGuestDelegate* CreateAppViewGuestDelegate() const;
 
+  // Creates a delegate for MimeHandlerViewGuest.
+  virtual scoped_ptr<MimeHandlerViewGuestDelegate>
+      CreateMimeHandlerViewGuestDelegate(MimeHandlerViewGuest* guest) const;
+
   // Returns a delegate for some of WebViewGuest's behavior. The caller owns the
   // returned WebViewGuestDelegate.
   virtual WebViewGuestDelegate* CreateWebViewGuestDelegate (