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/ReadPixBench.cpp b/bench/ReadPixBench.cpp
index f62917b..f761e33 100644
--- a/bench/ReadPixBench.cpp
+++ b/bench/ReadPixBench.cpp
@@ -24,7 +24,7 @@
         return "readpix";
     }
 
-    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+    virtual void onDraw(const int loops, SkCanvas* canvas) SK_OVERRIDE {
         canvas->clear(SK_ColorBLACK);
 
         SkISize size = canvas->getDeviceSize();
@@ -45,7 +45,7 @@
 
         bitmap.setConfig(SkBitmap::kARGB_8888_Config, kWindowSize, kWindowSize);
 
-        for (int i = 0; i < this->getLoops(); i++) {
+        for (int i = 0; i < loops; i++) {
             for (int x = 0; x < kNumStepsX; ++x) {
                 for (int y = 0; y < kNumStepsY; ++y) {
                     canvas->readPixels(&bitmap, x * offX, y * offY);