New FRAME_DURATION VideoFrameMetadata, with Cast Streaming use case.

content/browser/media/capture/video_capture_oracle.cc

 // Copyright (c) 2013 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 "content/browser/media/capture/video_capture_oracle.h"
 
 #include <algorithm>
 
 #include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
@@ skipping 42 matching lines @@
   DCHECK_GE(event, 0);
   DCHECK_LT(event, kNumEvents);
   if (event_time < last_event_time_[event]) {
     LOG(WARNING) << "Event time is not monotonically non-decreasing.  "
                  << "Deciding not to capture this frame.";
     return false;
   }
   last_event_time_[event] = event_time;
 
   bool should_sample;
+  duration_of_next_frame_ = base::TimeDelta();
   switch (event) {
     case kCompositorUpdate:
       smoothing_sampler_.ConsiderPresentationEvent(event_time);
       content_sampler_.ConsiderPresentationEvent(damage_rect, event_time);
       if (content_sampler_.HasProposal()) {
         should_sample = content_sampler_.ShouldSample();
-        if (should_sample)
+        if (should_sample) {
           event_time = content_sampler_.frame_timestamp();
+          duration_of_next_frame_ = content_sampler_.sampling_period();
+        }
       } else {
         should_sample = smoothing_sampler_.ShouldSample();
+        if (should_sample)
+          duration_of_next_frame_ = smoothing_sampler_.min_capture_period();
       }
       break;
     default:
       should_sample = smoothing_sampler_.IsOverdueForSamplingAt(event_time);
+      if (should_sample)
+        duration_of_next_frame_ = smoothing_sampler_.min_capture_period();
       break;
   }
 
   SetFrameTimestamp(frame_number_, event_time);
   return should_sample;
 }
 
 int VideoCaptureOracle::RecordCapture() {
   smoothing_sampler_.RecordSample();
   content_sampler_.RecordSample(GetFrameTimestamp(frame_number_));
@@ skipping 51 matching lines @@
   DCHECK_LT(frame_number_ - frame_number, kMaxFrameTimestamps);
   return frame_timestamps_[frame_number % kMaxFrameTimestamps];
 }
 
 void VideoCaptureOracle::SetFrameTimestamp(int frame_number,
                                            base::TimeTicks timestamp) {
   frame_timestamps_[frame_number % kMaxFrameTimestamps] = timestamp;
 }
 
 }  // namespace content