Change WebTimeRange to use doubles instead of floats.

public/platform/WebTimeRange.h

 /*
  * Copyright (C) 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 19 matching lines @@
 
 #ifndef WebTimeRange_h
 #define WebTimeRange_h
 
 #include "WebVector.h"
 
 namespace blink {
 
 struct WebTimeRange {
     WebTimeRange() : start(0), end(0) { }
-    WebTimeRange(float s, float e) : start(s), end(e) { }
+    WebTimeRange(double s, double e) : start(s), end(e) { }
 
-    float start;
-    float end;
+    double start;
+    double end;
 };
 
 typedef WebVector<WebTimeRange> WebTimeRanges;
 
 } // namespace blink
 
 #endif