Remove PlatformClientAuth interface from upstream.

chromecast/common/BUILD.gn

Index: chromecast/common/BUILD.gn
diff --git a/chromecast/common/BUILD.gn b/chromecast/common/BUILD.gn
index 0c76b30b9f14dd762bd4078ef3068d79f18bb678..d1765f12004f9e8bfbbd6721a0ad5c9bc2e7ef51 100644
--- a/chromecast/common/BUILD.gn
+++ b/chromecast/common/BUILD.gn
@@ -2,8 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//chromecast/chromecast.gni")
-
 source_set("common") {
   sources = [
     "cast_content_client.cc",
@@ -23,21 +21,4 @@ source_set("common") {
     "//ui/gfx",
     "//url:url",
   ]
-
-  public_deps = [
-    ":platform_client_auth",
-  ]
-}
-
-# target for definition and a simple implementation of PlatformClientAuth
-# b/30398176 components that depend on PlatformClientAuth should directly
-# depend on this target instead of //chromecast/common/
-source_set("platform_client_auth") {
-  sources = [
-    "platform_client_auth.h",
-  ]
-
-  if (chromecast_branding == "public") {
-    sources += [ "platform_client_auth_simple.cc" ]
-  }
 }