Send less data in the DataSender test that timed out under valgrind.

extensions/renderer/api/serial/data_sender_unittest.cc

Index: extensions/renderer/api/serial/data_sender_unittest.cc
diff --git a/extensions/renderer/api/serial/data_sender_unittest.cc b/extensions/renderer/api/serial/data_sender_unittest.cc
index 8fa9251bfced7e26b2129071e83b8be0fbf46d23..23e540f2c9884d1c8a3ea81e2dbe7f5b948c90e8 100644
--- a/extensions/renderer/api/serial/data_sender_unittest.cc
+++ b/extensions/renderer/api/serial/data_sender_unittest.cc
@@ -97,9 +97,9 @@ TEST_F(DataSenderTest, Send) {
 }
 
 TEST_F(DataSenderTest, LargeSend) {
-  std::string pattern = "1234567890";
+  std::string pattern = "123";
   std::string expected_data;
-  for (int i = 0; i < 110; i++)
+  for (int i = 0; i < 11; i++)
     expected_data += pattern;
   expected_data_.push(expected_data);
   RunTest("data_sender_unittest.js", "testLargeSend");