Move httpbase.cc and httpbase.h to test target.

It is used only by the test-only http server code.

Bug: webrtc:6424
Change-Id: Id7120ed1ded6773f98472526e8fa282cf0a423e8
Reviewed-on: https://webrtc-review.googlesource.com/33401
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21313}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 0949f4e..41bd74e 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -577,8 +577,6 @@
     "gunit_prod.h",
     "helpers.cc",
     "helpers.h",
-    "httpbase.cc",
-    "httpbase.h",
     "httpcommon-inl.h",
     "httpcommon.cc",
     "httpcommon.h",
@@ -822,6 +820,8 @@
     "firewallsocketserver.cc",
     "firewallsocketserver.h",
     "gunit.h",
+    "httpbase.cc",
+    "httpbase.h",
     "httpserver.cc",
     "httpserver.h",
     "md5.cc",