Remove const from `const int loops`.

This drives me nuts, and prevents `while (loops --> 0)`.

BUG=skia:

Review URL: https://codereview.chromium.org/1379923005
diff --git a/bench/ChromeBench.cpp b/bench/ChromeBench.cpp
index 231d09b..94c3f25 100644
--- a/bench/ChromeBench.cpp
+++ b/bench/ChromeBench.cpp
@@ -461,7 +461,7 @@
 protected:
 
     virtual const char* onGetName() { return "chrome_scrollGmail"; }
-    virtual void onDraw(const int loops, SkCanvas* canvas) {
+    virtual void onDraw(int loops, SkCanvas* canvas) {
         SkDEBUGCODE(this->validateBounds(canvas));
         SkPaint paint;
         this->setupPaint(&paint);