add realloc method to SkAutoSTMalloc

tests/TemplatesTest.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 "SkTemplates.h"
+#include "Test.h"
+
+// Tests for some of the helpers in SkTemplates.h
+static void test_automalloc_realloc(skiatest::Reporter* reporter) {
+    SkAutoSTMalloc<1, int> array;
+
+    // test we have a valid pointer, should not crash
+    array[0] = 1;
+    REPORTER_ASSERT(reporter, array[0] == 1);
+
+    // using realloc for init
+    array.realloc(1);
+
+    array[0] = 1;
+    REPORTER_ASSERT(reporter, array[0] == 1);
+
+    // verify realloc can grow
+    array.realloc(2);
+    REPORTER_ASSERT(reporter, array[0] == 1);
+
+    // realloc can shrink
+    array.realloc(1);
+    REPORTER_ASSERT(reporter, array[0] == 1);
+
+    // should not crash
+    array.realloc(0);
+
+    // grow and shrink again
+    array.realloc(10);
+    for (int i = 0; i < 10; i++) {
+        array[i] = 10 - i;
+    }
+    array.realloc(20);
+    for (int i = 0; i < 10; i++) {
+        REPORTER_ASSERT(reporter, array[i] == 10 - i);
+    }
+    array.realloc(10);
+    for (int i = 0; i < 10; i++) {
+        REPORTER_ASSERT(reporter, array[i] == 10 - i);
+    }
+
+    array.realloc(1);
+    REPORTER_ASSERT(reporter, array[0] = 10);
+
+    // resets mixed with realloc, below stack alloc size
+    array.reset(0);
+    array.realloc(1);
+    array.reset(1);
+
+    array[0] = 1;
+    REPORTER_ASSERT(reporter, array[0] == 1);
+
+    // reset and realloc > stack size
+    array.reset(2);
+    array.realloc(3);
+    array[0] = 1;
+    REPORTER_ASSERT(reporter, array[0] == 1);
+    array.realloc(1);
+    REPORTER_ASSERT(reporter, array[0] == 1);
+}
+
+DEF_TEST(Templates, reporter) {
+    test_automalloc_realloc(reporter);
+}