Revert of Use system timestamp as capture timestamp

media/capture/video/mac/video_capture_device_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/capture/video/mac/video_capture_device_mac.h"
 
 #include <IOKit/IOCFPlugIn.h>
 #include <IOKit/usb/IOUSBLib.h>
 #include <IOKit/usb/USBSpec.h>
 #include <stddef.h>
@@ skipping 527 matching lines @@
   // should not happen, it should resize internally.
   if (!AVFoundationGlue::IsAVFoundationSupported()) {
     capture_format_.frame_size = frame_format.frame_size;
   } else if (capture_format_.frame_size != frame_format.frame_size) {
     ReceiveError(FROM_HERE,
                  "Captured resolution " + frame_format.frame_size.ToString() +
                      ", and expected " + capture_format_.frame_size.ToString());
     return;
   }
 
+  base::TimeTicks aligned_timestamp;
+  if (timestamp == media::kNoTimestamp()) {
+    aligned_timestamp = base::TimeTicks::Now();
+  } else {
+    if (first_timestamp_ == media::kNoTimestamp()) {
+      first_timestamp_ = timestamp;
+      first_aligned_timestamp_ = base::TimeTicks::Now();
+    }
+    aligned_timestamp = first_aligned_timestamp_ + timestamp - first_timestamp_;
+  }
   client_->OnIncomingCapturedData(video_frame, video_frame_length, frame_format,
-                                  0, base::TimeTicks::Now());
+                                  0, aligned_timestamp);
 }
 
 void VideoCaptureDeviceMac::ReceiveError(
     const tracked_objects::Location& from_here,
     const std::string& reason) {
   task_runner_->PostTask(
       FROM_HERE, base::Bind(&VideoCaptureDeviceMac::SetErrorState,
                             weak_factory_.GetWeakPtr(), from_here, reason));
 }
 
@@ skipping 15 matching lines @@
   if (![capture_device_ setCaptureHeight:capture_format_.frame_size.height()
                                    width:capture_format_.frame_size.width()
                                frameRate:capture_format_.frame_rate]) {
     ReceiveError(FROM_HERE, "Could not configure capture device.");
     return false;
   }
   return true;
 }
 
 }  // namespace media