Change old PRG to be SkLCGRandom; change new one to SkRandom

bench/ChecksumBench.cpp

Index: bench/ChecksumBench.cpp
diff --git a/bench/ChecksumBench.cpp b/bench/ChecksumBench.cpp
index bc13ec5a558f85d3c5dab5abac3c12acc5471c12..315402eeee7f1aaa4e86bb0119aceb477d7a9351 100644
--- a/bench/ChecksumBench.cpp
+++ b/bench/ChecksumBench.cpp
@@ -30,7 +30,7 @@ class ComputeChecksumBench : public SkBenchmark {
 
 public:
     ComputeChecksumBench(void* param, ChecksumType type) : INHERITED(param), fType(type) {
-        SkMWCRandom rand;
+        SkRandom rand;
         for (int i = 0; i < U32COUNT; ++i) {
             fData[i] = rand.nextU();
         }