Make webrtc::ParseCandidate() public.

This is intended to be used in Blink to implement proper support
for the JavaScript RTCIceCandidate API.

Bug: chromium:683094
Change-Id: I93d117ef1bd9541593f2715bdf3291dc2941737f
Reviewed-on: https://webrtc-review.googlesource.com/c/119940
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Guido Urdaneta <guidou@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26404}

pc/webrtc_sdp.cc

diff --git a/pc/webrtc_sdp.cc b/pc/webrtc_sdp.cc
index 094525a..1b2ff15 100644
--- a/pc/webrtc_sdp.cc
+++ b/pc/webrtc_sdp.cc
@@ -335,10 +335,6 @@
                            std::string* parameter,
                            std::string* value,
                            SdpParseError* error);
-static bool ParseCandidate(const std::string& message,
-                           Candidate* candidate,
-                           SdpParseError* error,
-                           bool is_raw);
 static bool ParseRtcpFbAttribute(const std::string& line,
                                  const cricket::MediaType media_type,
                                  MediaContentDescription* media_desc,

pc/webrtc_sdp.h

diff --git a/pc/webrtc_sdp.h b/pc/webrtc_sdp.h
index 1d1e7aa..3ba5c7f 100644
--- a/pc/webrtc_sdp.h
+++ b/pc/webrtc_sdp.h
@@ -84,6 +84,17 @@
                                         cricket::Candidate* candidate,
                                         SdpParseError* error);
 
+// Parses |message| according to the grammar defined in RFC 5245, Section 15.1
+// and, if successful, stores the result in |candidate| and returns true.
+// If unsuccessful, returns false and stores error information in |error| if
+// |error| is not null.
+// If |is_raw| is false, |message| is expected to be prefixed with "a=".
+// If |is_raw| is true, no prefix is expected in |messaage|.
+RTC_EXPORT bool ParseCandidate(const std::string& message,
+                               cricket::Candidate* candidate,
+                               SdpParseError* error,
+                               bool is_raw);
+
 }  // namespace webrtc
 
 #endif  // PC_WEBRTC_SDP_H_