Update python print to use brackets

TBR=davidben

Bug: 1029339
Change-Id: I30603f483290d1d6fb59d484493222522a3bc490
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1942812
Commit-Queue: Chris Sharp <csharp@chromium.org>
Reviewed-by: Chris Sharp <csharp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720030}

net/test/python_utils_unittest.cc

@@ -39,7 +39,7 @@ TEST(PythonUtils, PythonRunTime) {
   // we want.
   cmd_line.AppendArg("-c");
   std::string input("PythonUtilsTest");
-  std::string python_cmd = base::StringPrintf("print '%s';", input.c_str());
+  std::string python_cmd = base::StringPrintf("print('%s');", input.c_str());
   cmd_line.AppendArg(python_cmd);
   std::string output;
   EXPECT_TRUE(base::GetAppOutput(cmd_line, &output));