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/MatrixConvolutionBench.cpp b/bench/MatrixConvolutionBench.cpp
index 161fc23..db25d99 100644
--- a/bench/MatrixConvolutionBench.cpp
+++ b/bench/MatrixConvolutionBench.cpp
@@ -40,7 +40,7 @@
         this->setupPaint(&paint);
         paint.setAntiAlias(true);
         SkRandom rand;
-        for (int i = 0; i < SkBENCHLOOP(3); i++) {
+        for (int i = 0; i < this->getLoops(); i++) {
             SkRect r = SkRect::MakeWH(rand.nextUScalar1() * 400,
                                       rand.nextUScalar1() * 400);
             paint.setImageFilter(fFilter);