Move more sources from modules.gypi to subdirectories.

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

Index: third_party/WebKit/Source/modules/credentialmanager/BUILD.gn
diff --git a/third_party/WebKit/Source/modules/credentialmanager/BUILD.gn b/third_party/WebKit/Source/modules/credentialmanager/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..783f1576c3425c54b1f8823fa3e31c3bf101ea47
--- /dev/null
+++ b/third_party/WebKit/Source/modules/credentialmanager/BUILD.gn
@@ -0,0 +1,24 @@
+# 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("credentialmanager") {
+  sources = [
+    "Credential.cpp",
+    "Credential.h",
+    "CredentialManagerClient.cpp",
+    "CredentialManagerClient.h",
+    "CredentialsContainer.cpp",
+    "CredentialsContainer.h",
+    "FederatedCredential.cpp",
+    "FederatedCredential.h",
+    "NavigatorCredentials.cpp",
+    "NavigatorCredentials.h",
+    "PasswordCredential.cpp",
+    "PasswordCredential.h",
+    "SiteBoundCredential.cpp",
+    "SiteBoundCredential.h",
+  ]
+}