Upgrade V8 Benchmark from v4 to v6.

chrome/test/data/v8_benchmark/README.txt

Index: chrome/test/data/v8_benchmark/README.txt
diff --git a/chrome/test/data/v8_benchmark/README.txt b/chrome/test/data/v8_benchmark/README.txt
index 7531157c369347e960066e420c34352c6f0ca2d7..6676f37556e425a020ab3337f531b8f531b77d21 100644
--- a/chrome/test/data/v8_benchmark/README.txt
+++ b/chrome/test/data/v8_benchmark/README.txt
@@ -52,3 +52,28 @@ memory management subsystem of the JavaScript engine.
 Furthermore, all the unused parts of the Prototype library were
 removed from the RayTrace benchmark. This does not affect the running
 of the benchmark.
+
+
+Changes from Version 4 to Version 5
+===================================
+
+Removed duplicate line in random seed code, and changed the name of
+the Object.prototype.inherits function in the DeltaBlue benchmark to
+inheritsFrom to avoid name clashes when running in Chromium with
+extensions enabled.
+
+
+Changes from Version 5 to Version 6
+===================================
+
+Removed dead code from the RayTrace benchmark and fixed a couple of
+typos in the DeltaBlue implementation. Changed the Splay benchmark to
+avoid converting the same numeric key to a string over and over again
+and to avoid inserting and removing the same element repeatedly thus
+increasing pressure on the memory subsystem. Changed the RegExp
+benchmark to exercise the regular expression engine on different
+input strings.
+
+Furthermore, the benchmark runner was changed to run the benchmarks
+for at least a few times to stabilize the reported numbers on slower
+machines.