Add base/parse_number.h to generalize number parsing done in //net.

net/base/parse_number_unittest.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/base/parse_number.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace net {
+namespace {
+
+TEST(ParseNumberTest, IntValidInputs) {
+  struct {
+    const char* input;
+    int output;
+  } tests[] = {

[mmenke, 2016/03/23 19:32:28]

+const

tests -> kTests

+      {"0", 0}, {"00000", 0}, {"003", 3}, {"003", 3}, {"1234566", 1234566},

[mmenke, 2016/03/23 19:32:28]

You have no test that we can handle digits in decreasing order!  </silliness>

[eroman, 2016/03/23 19:50:30]

Done

+  };
+
+  for (const auto& test : tests) {
+    int result;
+    ASSERT_TRUE(ParseNonNegativeDecimalInt(test.input, &result))
+        << "Failed to parse: " << test.input;
+    EXPECT_EQ(result, test.output) << "Failed to parse: " << test.input;
+  }
+}
+
+TEST(ParseNumberTest, IntInvalidInputs) {
+  const char* tests[] = {
+      "",
+      "-23",
+      "+42",
+      " 123",
+      "123 ",
+      "123\n",
+      "0xFF",

[mmenke, 2016/03/23 19:32:28]

0x11?  Just checking hex value with non-hex chars.  Not that it's likely to
regress independently, but the cost of extra cases here is pretty low.

[eroman, 2016/03/23 19:50:30]

Good idea. Done.

+      "AF",
+      "0AF",
+      "0.0",
+      "13.",
+      "13,000",
+      "13.000",
+      "13/5",
+      "9999999999999999999999999999999999999999999999999999999999999999",
+      "Inf",
+      "NaN",
+      "null",
+      "dog",
+  };
+
+  for (const auto& input : tests) {
+    int result = 0xDEAD;
+    ASSERT_FALSE(ParseNonNegativeDecimalInt(input, &result))
+        << "Succeeded to parse: " << input;
+    EXPECT_EQ(0xDEAD, result) << "Modified output for failed parsing";
+  }
+}
+
+TEST(ParseNumberTest, IntInvalidInputsContainsNul) {
+  int result = 0xDEAD;
+  ASSERT_FALSE(
+      ParseNonNegativeDecimalInt(base::StringPiece("123\0", 4), &result));
+  EXPECT_EQ(0xDEAD, result);
+}
+
+}  // namespace
+}  // namespace net