Revert "[scenic] Prepare session_shell for eventpairs"

This reverts commit 8082f8cf181730dd33d68d74c388025d05b7e202.

Reason for revert: Landed out of order with v/g, so breaks flamingo

Original change's description:
> [scenic] Prepare session_shell for eventpairs
> 
> TEST: CQ
> SCN-897 #comment
> SCN-1018 #comment
> SCN-1033 #comment
> 
> Change-Id: Ic2a6c432c5c534385a14d7e2e8fd7fe83b7c8eca

TBR=mikejurka@google.com,thatguy@google.com,jaeheon@google.com,dworsham@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I81df5690149b53e79771e7a2da3104b94fa2ad34
diff --git a/public/fidl/fuchsia.modular/BUILD.gn b/public/fidl/fuchsia.modular/BUILD.gn
index c762d98..e2f1cb8 100644
--- a/public/fidl/fuchsia.modular/BUILD.gn
+++ b/public/fidl/fuchsia.modular/BUILD.gn
@@ -76,7 +76,6 @@
     "//garnet/public/fidl/fuchsia.images",
     "//garnet/public/fidl/fuchsia.media",
     "//garnet/public/fidl/fuchsia.sys",
-    "//garnet/public/fidl/fuchsia.ui.gfx",
     "//garnet/public/fidl/fuchsia.ui.policy",
     "//garnet/public/fidl/fuchsia.ui.viewsv1token",
     "//peridot/public/fidl/fuchsia.ledger",
diff --git a/public/fidl/fuchsia.modular/session/session_shell.fidl b/public/fidl/fuchsia.modular/session/session_shell.fidl
index 79f27d2..b1a421e 100644
--- a/public/fidl/fuchsia.modular/session/session_shell.fidl
+++ b/public/fidl/fuchsia.modular/session/session_shell.fidl
@@ -6,23 +6,17 @@
 
 using fuchsia.modular.auth;
 using fuchsia.speech;
-using fuchsia.ui.gfx;
 using fuchsia.ui.policy;
 using fuchsia.ui.viewsv1token;
 
+
 // This interface is implemented by a session shell and is used by the
 // sessionmgr to hand to the session shell views of stories, or to notify that
 // the view of a story is about to be closed.
 [Discoverable]
 interface SessionShell {
-    // Instructs the session shell to display the given story view inside of
-    // its UI. The story this view belongs to is identified by
-    //|view_id.story_id|.
-    [Transitional]
-    AttachView2(ViewIdentifier view_id, fuchsia.ui.gfx.ImportToken view_holder_token);
-
-    // DEPRECATED
-    // TODO(SCN-1018): Remove.
+    // Displays the given story view. The story this view belongs to is
+    // identified by |view_id.story_id|.
     AttachView(ViewIdentifier view_id, fuchsia.ui.viewsv1token.ViewOwner view_owner);
 
     // Instructs the session shell to detach the view identified by |view_id|
@@ -51,7 +45,7 @@
 // This is a struct rather than a naked string to allow for future evolution of
 // the identifier without changing the |SessionShell| API itself.
 struct ViewIdentifier {
-    string story_id;
+  string story_id;
 };
 
 // This interface allows a |SessionShell| to request capabilities from its