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

net/base/host_port_pair_unittest.cc

 // Copyright (c) 2012 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/host_port_pair.h"
 
 #include "base/logging.h"
 #include "net/test/gtest_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 20 matching lines @@
 TEST(HostPortPairTest, Parsing) {
   HostPortPair foo("foo.com", 10);
   string foo_str = foo.ToString();
   EXPECT_EQ("foo.com:10", foo_str);
   HostPortPair bar = HostPortPair::FromString(foo_str);
   EXPECT_TRUE(foo.Equals(bar));
 }
 
 TEST(HostPortPairTest, BadString) {
   const char* kBadStrings[] = {
-    "foo.com:2:3",
-    "bar.com:two",
-    "www.google.com:-1",
-    "127.0.0.1:65536",
-    "[2001:db8::42]:65536",
+      "foo.com:2:3",       "bar.com:two",     "www.google.com:-1",
+      "www.google.com:+1", "127.0.0.1:65536", "[2001:db8::42]:65536",
   };
 
   for (size_t index = 0; index < arraysize(kBadStrings); ++index) {
     HostPortPair foo = HostPortPair::FromString(kBadStrings[index]);
     EXPECT_TRUE(foo.host().empty());
     EXPECT_EQ(0, foo.port());
   }
 }
 
 TEST(HostPortPairTest, Emptiness) {
@@ skipping 56 matching lines @@
 
   EXPECT_TRUE(new_a_10.Equals(a_10));
   EXPECT_FALSE(new_a_10.Equals(a_11));
   EXPECT_FALSE(new_a_10.Equals(b_10));
   EXPECT_FALSE(new_a_10.Equals(b_11));
 }
 
 }  // namespace
 
 }  // namespace net