Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/browser/renderer_host/DEPS

 include_rules = [
   "+cc/switches.h", # For cc command line switches.
   "+components/display_compositor",
   "+components/variations",
   "+services/ui/public",
   "+third_party/zlib",
 
   # The renderer_host files should only call upwards in the layering via the
   # delegate interfaces.
   "-content/browser/frame_host",
@@ skipping 27 matching lines @@
     "+content/browser/frame_host/frame_tree.h",
   ],
   "render_widget_host_view_aura\.cc": [
     "+content/browser/frame_host",
   ],
   "render_widget_host_view_event_handler\.cc": [
     "+content/browser/frame_host",
   ],
   # TODO(kenrb): RenderWidgetHostViewChildFrame should eventually be moved
   # to content/renderer_host, at which time this can be removed.
+  # RenderWidgetHostViewGuest dependency is needed to allow for routing mouse
+  # events to the correct owner RenderWidgetHostViewBase. It should be removed
+  # when all inner WebContents are based on OOPIF structure (as opposed to
+  # BrowserPlugin).
   "render_widget_host_input_event_router.cc": [
     "+content/browser/frame_host/render_widget_host_view_child_frame.h",
+    "+content/browser/frame_host/render_widget_host_view_guest.h",
   ],
 }