Allow seeks to zero on streaming sources.

Source/core/html/TimeRanges.cpp

Index: Source/core/html/TimeRanges.cpp
diff --git a/Source/core/html/TimeRanges.cpp b/Source/core/html/TimeRanges.cpp
index 943eb93468f6899f8510f24fee18dce0a1abbc79..9c6456794a74e4559cb6126af4c4de43ac8174d4 100644
--- a/Source/core/html/TimeRanges.cpp
+++ b/Source/core/html/TimeRanges.cpp
@@ -184,19 +184,29 @@ bool TimeRanges::contain(double time) const
 
 double TimeRanges::nearest(double time) const
 {
-    double closest = 0;
     unsigned count = length();
+    double 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 (time >= startTime && time <= endTime)
             return time;
-        if (fabs(startTime - time) < closest)
-            closest = fabs(startTime - time);
-        else if (fabs(endTime - time) < closest)
-            closest = fabs(endTime - time);
+        if (time < startTime) {
+            double delta = startTime - time;
+            if (delta < bestDelta) {
+                bestMatch = startTime;
+                bestDelta = delta;
+            }
+        } else if (time > endTime) {
+            double delta = time - endTime;
+            if (delta < bestDelta) {
+                bestMatch = endTime;
+                bestDelta = delta;
+            }
+        }
     }
-    return closest;
+    return bestMatch;
 }
 
 void TimeRanges::trace(Visitor* visitor)