Complete removing Blink gyp files.

third_party/WebKit/Source/modules/mediasession/BUILD.gn

Index: third_party/WebKit/Source/modules/mediasession/BUILD.gn
diff --git a/third_party/WebKit/Source/modules/mediasession/BUILD.gn b/third_party/WebKit/Source/modules/mediasession/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..b4622a82446330c5f72ba9726ef80f7d68726285
--- /dev/null
+++ b/third_party/WebKit/Source/modules/mediasession/BUILD.gn
@@ -0,0 +1,20 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//third_party/WebKit/Source/modules/modules.gni")
+
+blink_modules_sources("mediasession") {
+  sources = [
+    "HTMLMediaElementMediaSession.cpp",
+    "HTMLMediaElementMediaSession.h",
+    "MediaArtwork.cpp",
+    "MediaArtwork.h",
+    "MediaMetadata.cpp",
+    "MediaMetadata.h",
+    "MediaSession.cpp",
+    "MediaSession.h",
+    "MediaSessionError.cpp",
+    "MediaSessionError.h",
+  ]
+}