Simplify benchmark internal API.

I'm not quite sure why I wrote such a convoluted API with setLoops()/getLoops().
This replaces it with a loops argument passed to onDraw().

This CL is largely mechanical translation from the old API to the new one.
MathBench used this->getLoops() outside onDraw(), which seems incorrect.  I
fixed it.

BUG=
R=djsollen@google.com

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/99893003

git-svn-id: http://skia.googlecode.com/svn/trunk@12466 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/MutexBench.cpp b/bench/MutexBench.cpp
index bec0c80..3191ce1 100644
--- a/bench/MutexBench.cpp
+++ b/bench/MutexBench.cpp
@@ -18,9 +18,9 @@
         return "mutex";
     }
 
-    virtual void onDraw(SkCanvas*) {
+    virtual void onDraw(const int loops, SkCanvas*) {
         SK_DECLARE_STATIC_MUTEX(mu);
-        for (int i = 0; i < this->getLoops(); i++) {
+        for (int i = 0; i < loops; i++) {
             mu.acquire();
             mu.release();
         }