Major bench refactoring.
   - Use FLAGS_.
   - Remove outer repeat loop.
   - Tune inner loop automatically.

BUG=skia:1590
R=epoger@google.com, scroggo@google.com

Review URL: https://codereview.chromium.org/23478013

git-svn-id: http://skia.googlecode.com/svn/trunk@11187 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/WritePixelsBench.cpp b/bench/WritePixelsBench.cpp
index 7803a6d..a9b6763 100644
--- a/bench/WritePixelsBench.cpp
+++ b/bench/WritePixelsBench.cpp
@@ -56,14 +56,12 @@
         bmp.setConfig(SkBitmap::kARGB_8888_Config, size.width(), size.height());
         canvas->readPixels(&bmp, 0, 0);
 
-        for (int loop = 0; loop < kLoopCount; ++loop) {
+        for (int loop = 0; loop < this->getLoops(); ++loop) {
             canvas->writePixels(bmp, 0, 0, fConfig);
         }
     }
 
 private:
-    static const int kLoopCount = SkBENCHLOOP(50);
-
     SkCanvas::Config8888 fConfig;
     SkString             fName;