Delete class StringRtpHeaderExtension, replaced with std::string

Bug: webrtc:10440
Change-Id: I52f865496f9838ac0981a6cd13f24b5b681b6616
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128609
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27265}
diff --git a/modules/rtp_rtcp/source/rtp_header_extensions.cc b/modules/rtp_rtcp/source/rtp_header_extensions.cc
index 1d76ff3..9045003 100644
--- a/modules/rtp_rtcp/source/rtp_header_extensions.cc
+++ b/modules/rtp_rtcp/source/rtp_header_extensions.cc
@@ -727,24 +727,6 @@
 }
 
 bool BaseRtpStringExtension::Parse(rtc::ArrayView<const uint8_t> data,
-                                   StringRtpHeaderExtension* str) {
-  if (data.empty() || data[0] == 0)  // Valid string extension can't be empty.
-    return false;
-  str->Set(data);
-  RTC_DCHECK(!str->empty());
-  return true;
-}
-
-bool BaseRtpStringExtension::Write(rtc::ArrayView<uint8_t> data,
-                                   const StringRtpHeaderExtension& str) {
-  RTC_DCHECK_EQ(data.size(), str.size());
-  RTC_DCHECK_GE(str.size(), 1);
-  RTC_DCHECK_LE(str.size(), StringRtpHeaderExtension::kMaxSize);
-  memcpy(data.data(), str.data(), str.size());
-  return true;
-}
-
-bool BaseRtpStringExtension::Parse(rtc::ArrayView<const uint8_t> data,
                                    std::string* str) {
   if (data.empty() || data[0] == 0)  // Valid string extension can't be empty.
     return false;
@@ -758,7 +740,7 @@
 
 bool BaseRtpStringExtension::Write(rtc::ArrayView<uint8_t> data,
                                    const std::string& str) {
-  if (str.size() > StringRtpHeaderExtension::kMaxSize) {
+  if (str.size() > kMaxValueSizeBytes) {
     return false;
   }
   RTC_DCHECK_EQ(data.size(), str.size());