Paint buffered range closest to the current play position

Source/core/html/TimeRanges.cpp

 /*
  * Copyright (C) 2007, 2009, 2010 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 193 matching lines @@
 
         if (delta < bestDelta || (delta == bestDelta
             && std::abs(currentPlaybackPosition - match) < std::abs(currentPlaybackPosition - bestMatch))) {
             bestDelta = delta;
             bestMatch = match;
         }
     }
     return bestMatch;
 }
 
+unsigned TimeRanges::nearestRange(double position) const
+{
+    unsigned count = length();
+    unsigned bestMatch = 0;
+    double bestDelta = std::numeric_limits<double>::infinity();
+    for (unsigned ndx = 0; ndx < count; ++ndx) {
+        double startTime = start(ndx, IGNORE_EXCEPTION);
+        double endTime = end(ndx, IGNORE_EXCEPTION);
+        if (position >= startTime && position <= endTime) {
+            return ndx;
+        }
+
+        double delta;
+        if (position < startTime) {
+            delta = startTime - position;
+        } else {
+            delta = position - endTime;
+        }
+
+        // Prioritize later ranges
+        if (delta <= bestDelta) {
+            bestDelta = delta;
+            bestMatch = ndx;
+        }
+    }
+
+    return bestMatch;
+}
+
 DEFINE_TRACE(TimeRanges)
 {
     visitor->trace(m_ranges);
 }