Make RTCStatsReport::ToString() return JSON-parseable string.

webrtc/stats/rtcstats.cc

Index: webrtc/stats/rtcstats.cc
diff --git a/webrtc/stats/rtcstats.cc b/webrtc/stats/rtcstats.cc
index 5d0a937e6f31c12abadc55fa95be9adfb4fac6da..73fc6a5f5073df4a56237f77e01f3150a52cd366 100644
--- a/webrtc/stats/rtcstats.cc
+++ b/webrtc/stats/rtcstats.cc
@@ -18,33 +18,33 @@ namespace webrtc {
 
 namespace {
 
-// Produces "{ a, b, c }". Works for non-vector |RTCStatsMemberInterface::Type|
+// Produces "[ a, b, c ]". Works for non-vector |RTCStatsMemberInterface::Type|
 // types.
 template<typename T>
 std::string VectorToString(const std::vector<T>& vector) {
   if (vector.empty())
-    return "{}";
+    return "[]";
   std::ostringstream oss;
-  oss << "{ " << rtc::ToString<T>(vector[0]);
+  oss << "[ " << rtc::ToString<T>(vector[0]);
   for (size_t i = 1; i < vector.size(); ++i) {
     oss << ", " << rtc::ToString<T>(vector[i]);
   }
-  oss << " }";
+  oss << " ]";
   return oss.str();
 }
 
-// Produces "{ \"a\", \"b\", \"c\" }". Works for vectors of both const char* and
+// Produces "[ \"a\", \"b\", \"c\" ]". Works for vectors of both const char* and
 // std::string element types.
 template<typename T>
 std::string VectorOfStringsToString(const std::vector<T>& strings) {
   if (strings.empty())
-    return "{}";
+    return "[]";
   std::ostringstream oss;
-  oss << "{ \"" << rtc::ToString<T>(strings[0]) << '\"';
+  oss << "[ \"" << rtc::ToString<T>(strings[0]) << '\"';
   for (size_t i = 1; i < strings.size(); ++i) {
     oss << ", \"" << rtc::ToString<T>(strings[i]) << '\"';
   }
-  oss << " }";
+  oss << " ]";
   return oss.str();
 }
 
@@ -73,20 +73,18 @@ bool RTCStats::operator!=(const RTCStats& other) const {
 
 std::string RTCStats::ToString() const {
   std::ostringstream oss;
-  oss << type() << " {\n  id: \"" << id_ << "\"\n  timestamp: "
-      << timestamp_us_ << '\n';
+  oss << "{\n  \"type\": \"" << type() << "\",\n  \"id\": \"" << id_
+      << "\",\n  \"timestamp\": " << timestamp_us_;
   for (const RTCStatsMemberInterface* member : Members()) {
-    oss << "  " << member->name() << ": ";
     if (member->is_defined()) {
+      oss << ",\n  \"" << member->name() << "\": ";
       if (member->is_string())
-        oss << '"' << member->ValueToString() << "\"\n";
+        oss << '"' << member->ValueToString() << '"';
       else
-        oss << member->ValueToString() << '\n';
-    } else {
-      oss << "undefined\n";
+        oss << member->ValueToString();
     }
   }
-  oss << '}';
+  oss << "\n}";
   return oss.str();
 }