Convert video quality test from a TEST_F to a TEST fixture.

The purpose is to make the fixture reusable in downstream
projects. The CL adds the following things to API:

- api/test/video_quality_test_fixture.h
- api/test/create_video_quality_test_fixture.h

The following things are moved to API:

- call/bitrate_constraints.h (api/bitrate_constraints.h)
- call/simulated_network.h (api/test/simulated_network.h)
- call/media_type.h (api/mediatypes.h)

These are required by the params struct passed to the
fixture. I didn't attempt to split the params struct into
an internal-only and public version in this CL, and as
a result we need to pull in the above things. They are
quite harmless though, so I think it's worth it in order
to avoid splitting up the test config struct.

This CL doesn't solve all the problems we need to
implement downstream tests; we probably need to upstream
tracing variants of FakeNetworkPipe for instance, but
that will come later. This puts in place the basic
structure for now.

Bug: None
Change-Id: I35e26ed126fad27bc7b2a465400291084f6ac911
Reviewed-on: https://webrtc-review.googlesource.com/69601
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23714}
diff --git a/pc/webrtcsdp.cc b/pc/webrtcsdp.cc
index d068470..70a0634 100644
--- a/pc/webrtcsdp.cc
+++ b/pc/webrtcsdp.cc
@@ -22,6 +22,7 @@
 #include <unordered_map>
 #include <vector>
 
+#include "api/mediatypes.h"
 #include "api/candidate.h"
 #include "api/cryptoparams.h"
 #include "api/jsepicecandidate.h"
@@ -232,7 +233,7 @@
 static void AddFmtpLine(const T& codec, std::string* message);
 static void BuildMediaDescription(const ContentInfo* content_info,
                                   const TransportInfo* transport_info,
-                                  const MediaType media_type,
+                                  const cricket::MediaType media_type,
                                   const std::vector<Candidate>& candidates,
                                   int msid_signaling,
                                   std::string* message);
@@ -240,11 +241,11 @@
                                        int sctp_port,
                                        bool use_sctpmap);
 static void BuildRtpContentAttributes(const MediaContentDescription* media_desc,
-                                      const MediaType media_type,
+                                      const cricket::MediaType media_type,
                                       int msid_signaling,
                                       std::string* message);
 static void BuildRtpMap(const MediaContentDescription* media_desc,
-                        const MediaType media_type,
+                        const cricket::MediaType media_type,
                         std::string* message);
 static void BuildCandidate(const std::vector<Candidate>& candidates,
                            bool include_ufrag,
@@ -275,7 +276,7 @@
     std::vector<JsepIceCandidate*>* candidates,
     SdpParseError* error);
 static bool ParseContent(const std::string& message,
-                         const MediaType media_type,
+                         const cricket::MediaType media_type,
                          int mline_index,
                          const std::string& protocol,
                          const std::vector<int>& payload_types,
@@ -298,12 +299,12 @@
                                  MediaContentDescription* media_desc,
                                  SdpParseError* error);
 static bool ParseRtpmapAttribute(const std::string& line,
-                                 const MediaType media_type,
+                                 const cricket::MediaType media_type,
                                  const std::vector<int>& payload_types,
                                  MediaContentDescription* media_desc,
                                  SdpParseError* error);
 static bool ParseFmtpAttributes(const std::string& line,
-                                const MediaType media_type,
+                                const cricket::MediaType media_type,
                                 MediaContentDescription* media_desc,
                                 SdpParseError* error);
 static bool ParseFmtpParam(const std::string& line,
@@ -315,7 +316,7 @@
                            SdpParseError* error,
                            bool is_raw);
 static bool ParseRtcpFbAttribute(const std::string& line,
-                                 const MediaType media_type,
+                                 const cricket::MediaType media_type,
                                  MediaContentDescription* media_desc,
                                  SdpParseError* error);
 static bool ParseIceOptions(const std::string& line,
@@ -1243,7 +1244,7 @@
 
 void BuildMediaDescription(const ContentInfo* content_info,
                            const TransportInfo* transport_info,
-                           const MediaType media_type,
+                           const cricket::MediaType media_type,
                            const std::vector<Candidate>& candidates,
                            int msid_signaling,
                            std::string* message) {
@@ -1477,7 +1478,7 @@
 }
 
 void BuildRtpContentAttributes(const MediaContentDescription* media_desc,
-                               const MediaType media_type,
+                               const cricket::MediaType media_type,
                                int msid_signaling,
                                std::string* message) {
   std::ostringstream os;
@@ -1767,7 +1768,7 @@
 }
 
 void BuildRtpMap(const MediaContentDescription* media_desc,
-                 const MediaType media_type,
+                 const cricket::MediaType media_type,
                  std::string* message) {
   RTC_DCHECK(message != NULL);
   RTC_DCHECK(media_desc != NULL);
@@ -2328,7 +2329,7 @@
 
 template <class C>
 static C* ParseContentDescription(const std::string& message,
-                                  const MediaType media_type,
+                                  const cricket::MediaType media_type,
                                   int mline_index,
                                   const std::string& protocol,
                                   const std::vector<int>& payload_types,
@@ -2709,7 +2710,7 @@
 }
 
 bool ParseContent(const std::string& message,
-                  const MediaType media_type,
+                  const cricket::MediaType media_type,
                   int mline_index,
                   const std::string& protocol,
                   const std::vector<int>& payload_types,
@@ -3198,7 +3199,7 @@
 }
 
 bool ParseRtpmapAttribute(const std::string& line,
-                          const MediaType media_type,
+                          const cricket::MediaType media_type,
                           const std::vector<int>& payload_types,
                           MediaContentDescription* media_desc,
                           SdpParseError* error) {
@@ -3281,7 +3282,7 @@
 }
 
 bool ParseFmtpAttributes(const std::string& line,
-                         const MediaType media_type,
+                         const cricket::MediaType media_type,
                          MediaContentDescription* media_desc,
                          SdpParseError* error) {
   if (media_type != cricket::MEDIA_TYPE_AUDIO &&
@@ -3345,7 +3346,7 @@
 }
 
 bool ParseRtcpFbAttribute(const std::string& line,
-                          const MediaType media_type,
+                          const cricket::MediaType media_type,
                           MediaContentDescription* media_desc,
                           SdpParseError* error) {
   if (media_type != cricket::MEDIA_TYPE_AUDIO &&