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

The goal here is to get people to start using the new random number
generator, while leaving the old one in place so we don't have to 
rebaseline GMs.

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

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/23576015

git-svn-id: http://skia.googlecode.com/svn/trunk@11169 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/MathBench.cpp b/bench/MathBench.cpp
index 5470924..32a89d6 100644
--- a/bench/MathBench.cpp
+++ b/bench/MathBench.cpp
@@ -26,7 +26,7 @@
     MathBench(void* param, const char name[]) : INHERITED(param) {
         fName.printf("math_%s", name);
 
-        SkMWCRandom rand;
+        SkRandom rand;
         for (int i = 0; i < kBuffer; ++i) {
             fSrc[i] = rand.nextSScalar1();
         }
@@ -254,7 +254,7 @@
 public:
 
     IsFiniteBench(void* param, int index) : INHERITED(param) {
-        SkMWCRandom rand;
+        SkRandom rand;
 
         for (int i = 0; i < N; ++i) {
             fData[i] = rand.nextSScalar1();
@@ -322,7 +322,7 @@
 public:
 
     FloorBench(void* param, bool fast) : INHERITED(param), fFast(fast) {
-        SkMWCRandom rand;
+        SkRandom rand;
 
         for (int i = 0; i < ARRAY; ++i) {
             fData[i] = rand.nextSScalar1();
@@ -340,7 +340,7 @@
 
 protected:
     virtual void onDraw(SkCanvas*) {
-        SkMWCRandom rand;
+        SkRandom rand;
         float accum = 0;
         const float* data = fData;
 
@@ -384,7 +384,7 @@
         : INHERITED(param)
         , fUsePortable(usePortable) {
 
-        SkMWCRandom rand;
+        SkRandom rand;
         for (int i = 0; i < ARRAY; ++i) {
             fData[i] = rand.nextU();
         }
@@ -444,7 +444,7 @@
     NormalizeBench(void* param)
     : INHERITED(param) {
 
-        SkMWCRandom rand;
+        SkRandom rand;
         for (int i = 0; i < ARRAY; ++i) {
             fVec[i].set(rand.nextSScalar1(), rand.nextSScalar1());
         }
@@ -490,7 +490,7 @@
 public:
 
     FixedMathBench(void* param) : INHERITED(param) {
-        SkMWCRandom rand;
+        SkRandom rand;
         for (int i = 0; i < N; ++i) {
             fData[i] = rand.nextSScalar1();
         }