Crash Fix (Cast Streaming): Render overlay on copy of source frame.

media/cast/sender/performance_metrics_overlay.h

Index: media/cast/sender/performance_metrics_overlay.h
diff --git a/media/cast/sender/performance_metrics_overlay.h b/media/cast/sender/performance_metrics_overlay.h
index e9a66524b8bafc066e48b10fcf987feaec9ac7d4..774effe19da3606307bc94985d63f5655366646b 100644
--- a/media/cast/sender/performance_metrics_overlay.h
+++ b/media/cast/sender/performance_metrics_overlay.h
@@ -6,6 +6,7 @@
 #define MEDIA_CAST_SENDER_PERFORMANCE_METRICS_OVERLAY_H_
 
 #include "base/time/time.h"
+#include "media/base/video_frame.h"
 
 // This module provides a display of frame-level performance metrics, rendered
 // in the lower-right corner of a VideoFrame.  It looks like this:
@@ -48,25 +49,30 @@
 // media timestamp in minutes:seconds.hundredths format.
 
 namespace media {
-
-class VideoFrame;
-
 namespace cast {
 
-// Renders an overlay of frame-level performance metrics in the lower-right
-// corner of the |frame|, as described above.  The verbose logging level for
-// video_frame_overlay.cc determines which lines, if any, are rendered: VLOG
-// level 1 renders the bottom line only, level 2 renders the bottom and middle
-// lines, and level 3 renders all three lines.  So, use the
-// --vmodule=performance_metrics_overlay=3 command line argument to turn on
-// rendering of the entire overlay.
-void MaybeRenderPerformanceMetricsOverlay(base::TimeDelta target_playout_delay,
-                                          bool in_low_latency_mode,
-                                          int target_bitrate,
-                                          int frames_ago,
-                                          double encoder_utilization,
-                                          double lossy_utilization,
-                                          VideoFrame* frame);
+// If the user has requested VideoFrames have a performance metrics overlay
+// rendered on them, this function copies the |source| frame and then renders an
+// overlay on the copy. Frame-level performance metrics will be rendered in the
+// lower-right corner of the frame, as described in the module-level comments
+// above.
+//
+// The verbose logging level for video_frame_overlay.cc determines which lines,
+// if any, are rendered: no VLOG level does nothing, level 1 renders the bottom
+// line only, level 2 renders the bottom and middle lines, and level 3 renders
+// all three lines. So, use the --vmodule=performance_metrics_overlay=3 command
+// line argument to turn on rendering of the entire overlay.
+//
+// Note: If |source| is an unsupported format, or no pixels need to be modified,
+// this function will just return |source|.
+scoped_refptr<VideoFrame> MaybeRenderPerformanceMetricsOverlay(
+    base::TimeDelta target_playout_delay,
+    bool in_low_latency_mode,
+    int target_bitrate,
+    int frames_ago,
+    double encoder_utilization,
+    double lossy_utilization,
+    scoped_refptr<VideoFrame> source);
 
 }  // namespace cast
 }  // namespace media