Move interface registration to OnConnect in RPH

blimp/engine/app/blimp_content_browser_client.h

Index: blimp/engine/app/blimp_content_browser_client.h
diff --git a/blimp/engine/app/blimp_content_browser_client.h b/blimp/engine/app/blimp_content_browser_client.h
index 24ae73408e57fc84ceb6ba98444598bc0a0b14d2..5c4b3a25e6765661f6962b58621d9d37dc301d88 100644
--- a/blimp/engine/app/blimp_content_browser_client.h
+++ b/blimp/engine/app/blimp_content_browser_client.h
@@ -6,6 +6,7 @@
 #define BLIMP_ENGINE_APP_BLIMP_CONTENT_BROWSER_CLIENT_H_
 
 #include "base/macros.h"
+#include "blimp/engine/mojo/blob_channel_service.h"
 #include "content/public/browser/content_browser_client.h"
 
 namespace content {
@@ -32,13 +33,13 @@ class BlimpContentBrowserClient : public content::ContentBrowserClient {
       const content::MainFunctionParams& parameters) override;
   void OverrideWebkitPrefs(content::RenderViewHost* render_view_host,
                            content::WebPreferences* prefs) override;
-  void ExposeInterfacesToRenderer(
-      shell::InterfaceRegistry* registry,
-      content::RenderProcessHost* render_process_host) override;
+  void ExposeInterfacesToRenderer(shell::Connection* connection) override;
 
   BlimpBrowserContext* GetBrowserContext();
 
  private:
+  void BindBlobChannel(mojom::BlobChannelRequest request);
+
   // Owned by BrowserMainLoop
   BlimpBrowserMainParts* blimp_browser_main_parts_ = nullptr;