diff --git a/webrtc/test/testsupport/trace_to_stderr.cc b/webrtc/test/testsupport/trace_to_stderr.cc
index efc6ddf599..97828ec7ae 100644
--- a/webrtc/test/testsupport/trace_to_stderr.cc
+++ b/webrtc/test/testsupport/trace_to_stderr.cc
@@ -20,7 +20,17 @@ namespace test {
 
 static const int kLevelFilter = kTraceError | kTraceWarning | kTraceTerseInfo;
 
-TraceToStderr::TraceToStderr() {
+TraceToStderr::TraceToStderr()
+    : override_time_(false),
+      time_seconds_(0) {
+  Trace::CreateTrace();
+  Trace::SetTraceCallback(this);
+  Trace::SetLevelFilter(kLevelFilter);
+}
+
+TraceToStderr::TraceToStderr(bool override_time)
+    : override_time_(override_time),
+      time_seconds_(0) {
   Trace::CreateTrace();
   Trace::SetTraceCallback(this);
   Trace::SetLevelFilter(kLevelFilter);
@@ -35,10 +45,14 @@ void TraceToStderr::Print(TraceLevel level, const char* msg_array, int length) {
   if (level & kLevelFilter) {
     assert(length > Trace::kBoilerplateLength);
     std::string msg = msg_array;
-    std::string msg_time = msg.substr(Trace::kTimestampPosition,
-                                      Trace::kTimestampLength);
     std::string msg_log = msg.substr(Trace::kBoilerplateLength);
-    fprintf(stderr, "%s %s\n", msg_time.c_str(), msg_log.c_str());
+    if (override_time_) {
+      fprintf(stderr, "%.2fs %s\n", time_seconds_, msg_log.c_str());
+    } else {
+      std::string msg_time = msg.substr(Trace::kTimestampPosition,
+                                        Trace::kTimestampLength);
+      fprintf(stderr, "%s %s\n", msg_time.c_str(), msg_log.c_str());
+    }
     fflush(stderr);
   }
 }
diff --git a/webrtc/test/testsupport/trace_to_stderr.h b/webrtc/test/testsupport/trace_to_stderr.h
index 40ff8795c0..1479834db9 100644
--- a/webrtc/test/testsupport/trace_to_stderr.h
+++ b/webrtc/test/testsupport/trace_to_stderr.h
@@ -21,9 +21,29 @@ namespace test {
 class TraceToStderr : public TraceCallback {
  public:
   TraceToStderr();
+  // Set |override_time| to true to control the time printed with each trace
+  // through SetTimeSeconds(). Otherwise, the trace's usual wallclock time is
+  // used.
+  //
+  // This is useful for offline test tools, where the file time is much more
+  // informative than the real time.
+  explicit TraceToStderr(bool override_time);
   virtual ~TraceToStderr();
 
+  // Every subsequent trace printout will use |time|. Has no effect if
+  // |override_time| in the constructor was set to false.
+  //
+  // No attempt is made to ensure thread-safety between the trace writing and
+  // time updating. In tests, since traces will normally be triggered by the
+  // main thread doing the time updating, this should be of no concern.
+  virtual void SetTimeSeconds(float time) { time_seconds_ = time; }
+
+  // Implements TraceCallback.
   virtual void Print(TraceLevel level, const char* msg_array, int length);
+
+ private:
+  bool override_time_;
+  float time_seconds_;
 };
 
 }  // namespace test