Order function definitions in base/ according to the header.

BUG=68682
TEST=compiles

Review URL: http://codereview.chromium.org/6085015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@70975 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/crypto/symmetric_key_nss.cc b/base/crypto/symmetric_key_nss.cc
index d291e8d..1e3551d 100644
--- a/base/crypto/symmetric_key_nss.cc
+++ b/base/crypto/symmetric_key_nss.cc
@@ -12,10 +12,6 @@
 
 namespace base {
 
-SymmetricKey::SymmetricKey(PK11SymKey* key) : key_(key) {
-  DCHECK(key);
-}
-
 SymmetricKey::~SymmetricKey() {}
 
 // static
@@ -124,4 +120,8 @@
   return true;
 }
 
+SymmetricKey::SymmetricKey(PK11SymKey* key) : key_(key) {
+  DCHECK(key);
+}
+
 }  // namespace base