Revert "Move webrtc/{base => rtc_base}" (https://codereview.webrtc.org/2877023002)

Will reland in two different commits to preserve git blame history.

BUG=webrtc:7634
NOTRY=True
TBR=kwiberg@webrtc.org

Change-Id: I550da8525aeb9c5b8f96338fcf1c9714f3dcdab1
Reviewed-on: https://chromium-review.googlesource.com/554610
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18820}
diff --git a/webrtc/base/dscp.h b/webrtc/base/dscp.h
index 1cf2756..970ff93 100644
--- a/webrtc/base/dscp.h
+++ b/webrtc/base/dscp.h
@@ -11,9 +11,35 @@
 #ifndef WEBRTC_BASE_DSCP_H_
 #define WEBRTC_BASE_DSCP_H_
 
+namespace rtc {
+// Differentiated Services Code Point.
+// See http://tools.ietf.org/html/rfc2474 for details.
+enum DiffServCodePoint {
+  DSCP_NO_CHANGE = -1,
+  DSCP_DEFAULT = 0,  // Same as DSCP_CS0
+  DSCP_CS0  = 0,   // The default
+  DSCP_CS1  = 8,   // Bulk/background traffic
+  DSCP_AF11 = 10,
+  DSCP_AF12 = 12,
+  DSCP_AF13 = 14,
+  DSCP_CS2  = 16,
+  DSCP_AF21 = 18,
+  DSCP_AF22 = 20,
+  DSCP_AF23 = 22,
+  DSCP_CS3  = 24,
+  DSCP_AF31 = 26,
+  DSCP_AF32 = 28,
+  DSCP_AF33 = 30,
+  DSCP_CS4  = 32,
+  DSCP_AF41 = 34,  // Video
+  DSCP_AF42 = 36,  // Video
+  DSCP_AF43 = 38,  // Video
+  DSCP_CS5  = 40,  // Video
+  DSCP_EF   = 46,  // Voice
+  DSCP_CS6  = 48,  // Voice
+  DSCP_CS7  = 56,  // Control messages
+};
 
-// This header is deprecated and is just left here temporarily during
-// refactoring. See https://bugs.webrtc.org/7634 for more details.
-#include "webrtc/rtc_base/dscp.h"
+}  // namespace rtc
 
-#endif  // WEBRTC_BASE_DSCP_H_
+ #endif  // WEBRTC_BASE_DSCP_H_