Force MimeHandlerView to always use BrowserPlugin

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index b636ed7eeac27488e1d5e80f2e24b0a33c7cc7d3..99f64603faee8a8a236a9bff7a951c77f46368f0 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -40,11 +40,11 @@
 #include "content/common/site_isolation_policy.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/content_browser_client.h"
+#include "content/public/browser/guest_mode.h"
 #include "content/public/browser/render_process_host_observer.h"
 #include "content/public/browser/render_widget_host_iterator.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/user_metrics.h"
-#include "content/public/common/browser_plugin_guest_mode.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/referrer.h"
@@ -1825,7 +1825,7 @@ void RenderFrameHostManager::EnsureRenderViewInitialized(
 void RenderFrameHostManager::CreateOuterDelegateProxy(
     SiteInstance* outer_contents_site_instance,
     RenderFrameHostImpl* render_frame_host) {
-  CHECK(BrowserPluginGuestMode::UseCrossProcessFramesForGuests());
+  CHECK(GuestMode::ForInnerWebContentsUsingCrossProcessFrames(current_host()));

[Charlie Reis, 2016/09/21 22:18:21]

This is just a sanity check, so I don't think we need the RVH version of the
method just for that.  (We're already doing the CHECK from the only callsite in
AttachToOuterWebContentsFrame.)

Let's remove the RVH version and just put a comment on the declaration of this
method in render_frame_host_manager.h, saying that it should only be called for
OOPIF-based inner WebContents.

[EhsanK, 2016/09/22 22:55:44]

Acknowledged.

   RenderFrameProxyHost* proxy =
       CreateRenderFrameProxyHost(outer_contents_site_instance, nullptr);