fix windows build

tests/HashTest.cpp

 #include "SkChecksum.h"
 #include "SkString.h"
 #include "SkTHash.h"
 #include "Test.h"
 
 namespace { uint32_t hash_int(int k) { return SkChecksum::Mix(k); } }
 
 static void set_negative_key(int key, double* d) { *d = -key; }
 
 DEF_TEST(HashMap, r) {
@@ skipping 23 matching lines @@
         REPORTER_ASSERT(r, found);
         REPORTER_ASSERT(r, *found == i*2.0);
     }
     for (int i = N; i < 2*N; i++) {
         REPORTER_ASSERT(r, !map.find(i));
     }
 
     REPORTER_ASSERT(r, map.count() == N);
 }
 
-namespace { uint32_t hash_string(SkString s) { return s.size(); } }
+namespace { uint32_t hash_string(SkString s) { return (uint32_t)s.size(); } }
 
 DEF_TEST(HashSet, r) {
     SkTHashSet<SkString, hash_string> set;
 
     set.add(SkString("Hello"));
     set.add(SkString("World"));
 
     REPORTER_ASSERT(r, set.count() == 2);
 
     REPORTER_ASSERT(r, set.contains(SkString("Hello")));
     REPORTER_ASSERT(r, set.contains(SkString("World")));
     REPORTER_ASSERT(r, !set.contains(SkString("Goodbye")));
 }