OSCrypt for POSIX uses libsecret to store a randomised encryption key.

components/os_crypt/BUILD.gn

Index: components/os_crypt/BUILD.gn
diff --git a/components/os_crypt/BUILD.gn b/components/os_crypt/BUILD.gn
index 6e37c63c8c280dead73a9d623ee963300ae0db4d..6f53770a51c085b7909cdcfffeeffd8c34612fed 100644
--- a/components/os_crypt/BUILD.gn
+++ b/components/os_crypt/BUILD.gn
@@ -42,9 +42,17 @@ source_set("os_crypt") {
   }
 
   if (is_desktop_linux) {
+    sources -= [ "os_crypt_posix.cc" ]
     sources += [
-      "libsecret_util_posix.cc",
-      "libsecret_util_posix.h",
+      "key_storage_libsecret.cc",
+      "key_storage_libsecret.h",
+      "key_storage_linux.cc",
+      "key_storage_linux.h",
+      "key_storage_mock.cc",
+      "key_storage_mock.h",
+      "libsecret_util_linux.cc",
+      "libsecret_util_linux.h",
+      "os_crypt_linux.cc",
     ]
     configs += [ "//build/config/linux:glib" ]
     deps += [ "//third_party/libsecret" ]
@@ -65,4 +73,10 @@ source_set("unit_tests") {
     "//crypto",
     "//testing/gtest",
   ]
+
+  if (is_desktop_linux) {
+    sources += [ "os_crypt_util_linux_unittest.cc" ]
+    deps += [ "//third_party/libsecret" ]

[Lei Zhang, 2016/05/18 22:38:15]

I can't remember if this is strictly necessary with GN since you already depend
on the os_crypt target. Care to double check?

[cfroussios, 2016/05/19 21:18:17]

We include libsecret_util_linux.h, which brings the <libsecret/secret.h>. The
dependency is needed to include the libsecret directory.

Alternatively, we can make the //third_party/libsecret configure all dependents.
That's an overkill, since os_crypt doesn't need to expose libsecret stuff.

+    defines = [ "USE_LIBSECRET" ]
+  }
 }