Convert SetVisuallyDeemphasized IPC to mojo

chrome/browser/ui/apps/chrome_app_delegate.cc

Index: chrome/browser/ui/apps/chrome_app_delegate.cc
diff --git a/chrome/browser/ui/apps/chrome_app_delegate.cc b/chrome/browser/ui/apps/chrome_app_delegate.cc
index 5b90605119028199a8b6255ab8900720ccef53b1..7b2b68508e89c2a3a8c51b55ee1d0513a9f0e0bb 100644
--- a/chrome/browser/ui/apps/chrome_app_delegate.cc
+++ b/chrome/browser/ui/apps/chrome_app_delegate.cc
@@ -34,11 +34,13 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/notification_service.h"
-#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "extensions/common/constants.h"
 #include "printing/features/features.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
 
 #if defined(USE_ASH)
 #include "ash/common/shelf/shelf_constants.h"  // nogncheck
@@ -305,10 +307,11 @@ void ChromeAppDelegate::SetWebContentsBlocked(
   if (!blocked)
     web_contents->Focus();
   // RenderViewHost may be NULL during shutdown.
-  content::RenderViewHost* host = web_contents->GetRenderViewHost();
+  content::RenderFrameHost* host = web_contents->GetMainFrame();
   if (host) {
-    host->Send(new ChromeViewMsg_SetVisuallyDeemphasized(host->GetRoutingID(),
-                                                         blocked));
+    host->GetProcess()->GetRemoteInterfaces()->GetInterface(
+        &extensions_frame_observer_);

[Devlin, 2017/03/04 02:19:41]

This re-gets the interface each time we send the message.  Seems like we should
be either caching the interface in a local variable, rather than a member
variable, or else checking whether or not its initialized before trying to get
it.  I think the former makes more sense here, since it appears the
ChromeAppDelegate can be used across multiple WebContents/RenderFrameHosts.

[catmullings, 2017/03/06 21:20:40]

Done.

+    extensions_frame_observer_->SetVisuallyDeemphasized(blocked);
   }
 }