Switch out random number generator for tests, benches, samples.

This change makes tests, benches and samples use the new SkMWCRandom PRNG. GMs will be saved for another time, as they'll require rebaselining.

R=reed@google.com, bsalomon@google.com

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/23653018

git-svn-id: http://skia.googlecode.com/svn/trunk@11136 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleVertices.cpp b/samplecode/SampleVertices.cpp
index 53db2ea..d71a1ae 100644
--- a/samplecode/SampleVertices.cpp
+++ b/samplecode/SampleVertices.cpp
@@ -144,7 +144,7 @@
 
     void make_tris(Rec* rec) {
         int n = 10;
-        SkRandom    rand;
+        SkMWCRandom    rand;
 
         rec->fMode = SkCanvas::kTriangles_VertexMode;
         rec->fCount = n * 3;