Adds a QuicUtil::HexDump method that provides better debug output of binary data.

net/quic/quic_utils_test.cc

Index: net/quic/quic_utils_test.cc
diff --git a/net/quic/quic_utils_test.cc b/net/quic/quic_utils_test.cc
index 7412a24052d71c43f7a7e87914fa1034b0aaa0eb..e8e864b15ab3be1242372d1341f6ce3266ddaf6c 100644
--- a/net/quic/quic_utils_test.cc
+++ b/net/quic/quic_utils_test.cc
@@ -185,6 +185,27 @@ TEST(QuicUtilsHashTest, ReferenceTest) {
                 reinterpret_cast<const char*>(data.data()), data.size()));
 }
 
+TEST(QuicUtilsTest, HexDump) {
+  // Verify output of the HexDump method is as expected.
+  char packet[] = {
+      0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20, 0x51, 0x55, 0x49, 0x43, 0x21,
+      0x20, 0x54, 0x68, 0x69, 0x73, 0x20, 0x73, 0x74, 0x72, 0x69, 0x6e, 0x67,
+      0x20, 0x73, 0x68, 0x6f, 0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x6c,
+      0x6f, 0x6e, 0x67, 0x20, 0x65, 0x6e, 0x6f, 0x75, 0x67, 0x68, 0x20, 0x74,
+      0x6f, 0x20, 0x73, 0x70, 0x61, 0x6e, 0x20, 0x6d, 0x75, 0x6c, 0x74, 0x69,
+      0x70, 0x6c, 0x65, 0x20, 0x6c, 0x69, 0x6e, 0x65, 0x73, 0x20, 0x6f, 0x66,
+      0x20, 0x6f, 0x75, 0x74, 0x70, 0x75, 0x74, 0x2e, 0x01, 0x02, 0x03, 0x00,
+  };
+  EXPECT_EQ(
+      QuicUtils::HexDump(packet),
+      "48 65 6C 6C 6F 2C 20 51 55 49 43 21 20 54 68 69  |Hello, QUIC! Thi|\n"
+      "73 20 73 74 72 69 6E 67 20 73 68 6F 75 6C 64 20  |s string should |\n"
+      "62 65 20 6C 6F 6E 67 20 65 6E 6F 75 67 68 20 74  |be long enough t|\n"
+      "6F 20 73 70 61 6E 20 6D 75 6C 74 69 70 6C 65 20  |o span multiple |\n"
+      "6C 69 6E 65 73 20 6F 66 20 6F 75 74 70 75 74 2E  |lines of output.|\n"
+      "01 02 03                                         |...             |\n");
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace net