Slim Skia down to just one murmur3 implementation.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/6ac0037b70410ff7d5ce5788bc89314223e1a587

R=reed@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/376183004
diff --git a/bench/FontCacheBench.cpp b/bench/FontCacheBench.cpp
index 0e75c9c..697bde6 100644
--- a/bench/FontCacheBench.cpp
+++ b/bench/FontCacheBench.cpp
@@ -7,6 +7,7 @@
 
 #include "Benchmark.h"
 #include "SkCanvas.h"
+#include "SkChecksum.h"
 #include "SkFontHost.h"
 #include "SkPaint.h"
 #include "SkString.h"
@@ -64,23 +65,12 @@
     return value ^ (value >> 8);
 }
 
-static uint32_t hasher2(uint32_t h) {
-    h ^= h >> 16;
-    h *= 0x85ebca6b;
-    h ^= h >> 13;
-    h *= 0xc2b2ae35;
-    h ^= h >> 16;
-
-    h ^= (h >> 8);
-    return h;
-}
-
 static const struct {
     const char* fName;
     HasherProc  fHasher;
 } gRec[] = {
     { "hasher0",  hasher0 },
-    { "hasher2",  hasher2 },
+    { "hasher2",  SkChecksum::Mix },
 };
 
 #define kMaxHashBits   12