Add approxBytesUsed to hashes.

tests/HashTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkChecksum.h"
 #include "SkString.h"
 #include "SkTHash.h"
 #include "Test.h"
 
 // Tests use of const foreach().  map.count() is of course the better way to do this.
 static int count(const SkTHashMap<int, double>& map) {
     int n = 0;
     map.foreach([&n](int, double) { n++; });
     return n;
 }
 
 DEF_TEST(HashMap, r) {
     SkTHashMap<int, double> map;
 
     map.set(3, 4.0);
     REPORTER_ASSERT(r, map.count() == 1);
 
+    REPORTER_ASSERT(r, map.approxBytesUsed() > 0);
+
     double* found = map.find(3);
     REPORTER_ASSERT(r, found);
     REPORTER_ASSERT(r, *found == 4.0);
 
     map.foreach([](int key, double* d){ *d = -key; });
     REPORTER_ASSERT(r, count(map) == 1);
 
     found = map.find(3);
     REPORTER_ASSERT(r, found);
     REPORTER_ASSERT(r, *found == -3.0);
@@ skipping 107 matching lines @@
     set.add(copyCounter2);
     REPORTER_ASSERT(r, globalCounter == 3);
     REPORTER_ASSERT(r, set.contains(copyCounter1));
     REPORTER_ASSERT(r, set.contains(copyCounter2));
     REPORTER_ASSERT(r, globalCounter == 3);
     set.add(copyCounter1);
     set.add(copyCounter2);
     // We allow copies for same-value adds for now.
     REPORTER_ASSERT(r, globalCounter == 5);
 }