Move socket_address_pair.h to webrtc namespace

Bug: webrtc:42232595
Change-Id: Ic46e80ab4d56f7f4acc800d289a356a5c4ad4460
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/380501
Auto-Submit: Evan Shrubsole <eshr@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#44077}
diff --git a/rtc_base/socket_address_pair.h b/rtc_base/socket_address_pair.h
index f315e64..aa1b01c 100644
--- a/rtc_base/socket_address_pair.h
+++ b/rtc_base/socket_address_pair.h
@@ -15,7 +15,7 @@
 
 #include "rtc_base/socket_address.h"
 
-namespace rtc {
+namespace webrtc {
 
 // Records a pair (source,destination) of socket addresses.  The two addresses
 // identify a connection between two machines.  (For UDP, this "connection" is
@@ -23,10 +23,11 @@
 class SocketAddressPair {
  public:
   SocketAddressPair() {}
-  SocketAddressPair(const SocketAddress& srs, const SocketAddress& dest);
+  SocketAddressPair(const rtc::SocketAddress& srs,
+                    const rtc::SocketAddress& dest);
 
-  const SocketAddress& source() const { return src_; }
-  const SocketAddress& destination() const { return dest_; }
+  const rtc::SocketAddress& source() const { return src_; }
+  const rtc::SocketAddress& destination() const { return dest_; }
 
   bool operator==(const SocketAddressPair& r) const;
   bool operator<(const SocketAddressPair& r) const;
@@ -34,10 +35,16 @@
   size_t Hash() const;
 
  private:
-  SocketAddress src_;
-  SocketAddress dest_;
+  rtc::SocketAddress src_;
+  rtc::SocketAddress dest_;
 };
 
+}  //  namespace webrtc
+
+// Re-export symbols from the webrtc namespace for backwards compatibility.
+// TODO(bugs.webrtc.org/4222596): Remove once all references are updated.
+namespace rtc {
+using ::webrtc::SocketAddressPair;
 }  // namespace rtc
 
 #endif  // RTC_BASE_SOCKET_ADDRESS_PAIR_H_