Add ThreadChecker to the TimestampAligner class.

webrtc/base/timestampaligner.cc

Index: webrtc/base/timestampaligner.cc
diff --git a/webrtc/base/timestampaligner.cc b/webrtc/base/timestampaligner.cc
index e03e4fb04eb9ca85a891c580f6335a46be46e8f8..66724399fe6daebdfc7fe118a29210921577bfa0 100644
--- a/webrtc/base/timestampaligner.cc
+++ b/webrtc/base/timestampaligner.cc
@@ -13,11 +13,16 @@
 
 namespace rtc {
 
-TimestampAligner::TimestampAligner() : frames_seen_(0), offset_us_(0) {}
+TimestampAligner::TimestampAligner() : frames_seen_(0), offset_us_(0) {
+  thread_checker_.DetachFromThread();
+}
+
 TimestampAligner::~TimestampAligner() {}
 
 int64_t TimestampAligner::UpdateOffset(int64_t camera_time_us,
                                        int64_t system_time_us) {
+  RTC_DCHECK(thread_checker_.CalledOnValidThread());
+
   // Estimate the offset between system monotonic time and the capture
   // time from the camera. The camera is assumed to provide more
   // accurate timestamps than we get from the system time. But the
@@ -86,6 +91,8 @@ int64_t TimestampAligner::UpdateOffset(int64_t camera_time_us,
 
 int64_t TimestampAligner::ClipTimestamp(int64_t time_us,
                                         int64_t system_time_us) {
+  RTC_DCHECK(thread_checker_.CalledOnValidThread());
+
   // Make timestamps monotonic.
   if (!prev_translated_time_us_) {
     // Initialize.