Allow GMs to be used as benchmarks. Make convex_poly_clip opt in.

R=reed@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/151843002

git-svn-id: http://skia.googlecode.com/svn/trunk@13279 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/SkBenchmark.h b/bench/SkBenchmark.h
index bf44d2c..f1e317d 100644
--- a/bench/SkBenchmark.h
+++ b/bench/SkBenchmark.h
@@ -13,9 +13,13 @@
 #include "SkString.h"
 #include "SkTRegistry.h"
 
-#define DEF_BENCH(code) \
-static SkBenchmark* SK_MACRO_APPEND_LINE(F_)() { code; } \
-static BenchRegistry SK_MACRO_APPEND_LINE(R_)(SK_MACRO_APPEND_LINE(F_));
+#define DEF_BENCH(code)                                                 \
+namespace {                                                             \
+class SK_MACRO_APPEND_LINE(F_CLASS) : public SkBenchmarkFactory {       \
+    virtual SkBenchmark* operator()() const SK_OVERRIDE { code; }       \
+} SK_MACRO_APPEND_LINE(g_F_);                                           \
+BenchRegistry SK_MACRO_APPEND_LINE(g_R_)(&SK_MACRO_APPEND_LINE(g_F_));  \
+}
 
 /*
  *  With the above macros, you can register benches as follows (at the bottom
@@ -132,6 +136,13 @@
     typedef SkRefCnt INHERITED;
 };
 
-typedef SkTRegistry<SkBenchmark*(*)()> BenchRegistry;
+class SkBenchmarkFactory : public SkRefCnt {
+public:
+    // Creates a new SkBenchmark that is owned by the caller on each call.
+    virtual SkBenchmark* operator()() const = 0;
+    virtual ~SkBenchmarkFactory() {}
+};
+
+typedef SkTRegistry<SkBenchmarkFactory*> BenchRegistry;
 
 #endif