tools: update inspector_protocol to a53e96d31a2755eb16ca37

Refs: https://chromium.googlesource.com/deps/inspector_protocol/+log

PR-URL: #39694
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: James M Snell <jasnell@gmail.com>

tools/inspector_protocol/encoding/encoding.cc

@@ -846,10 +846,12 @@ void CBORTokenizer::ReadNextToken(bool enter_envelope) {
           // inspector_protocol, it's not a CBOR limitation); in CBOR, the
           // negative values for INT32 are represented as NEGATIVE, that is, -1
           // INT32 is represented as 1 << 5 | 0 (major type 1, additional info
-          // value 0). The minimal allowed INT32 value in our protocol is
-          // std::numeric_limits<int32_t>::min(). We check for it by directly
-          // checking the payload against the maximal allowed signed (!) int32
-          // value.
+          // value 0).
+          // The represented allowed values range is -1 to -2^31.
+          // They are mapped into the encoded range of 0 to 2^31-1.
+          // We check the the payload in token_start_internal_value_ against
+          // that range (2^31-1 is also known as
+          // std::numeric_limits<int32_t>::max()).
           if (!success || token_start_internal_value_ >
                               std::numeric_limits<int32_t>::max()) {
             SetError(Error::CBOR_INVALID_INT32);

tools/inspector_protocol/encoding/encoding_test.cc

@@ -235,7 +235,9 @@ TEST(EncodeDecodeInt32Test, RoundtripsInt32Max) {
 }
 
 TEST(EncodeDecodeInt32Test, RoundtripsInt32Min) {
-  // std::numeric_limits<int32_t> is encoded as a uint32 after the initial byte.
+  // std::numeric_limits<int32_t> is encoded as a uint32 (4 unsigned bytes)
+  // after the initial byte, which effectively carries the sign by
+  // designating the token as NEGATIVE.
   std::vector<uint8_t> encoded;
   EncodeInt32(std::numeric_limits<int32_t>::min(), &encoded);
   // 1 for initial byte, 4 for the uint32.
@@ -248,6 +250,9 @@ TEST(EncodeDecodeInt32Test, RoundtripsInt32Min) {
   CBORTokenizer tokenizer(SpanFrom(encoded));
   EXPECT_EQ(CBORTokenTag::INT32, tokenizer.TokenTag());
   EXPECT_EQ(std::numeric_limits<int32_t>::min(), tokenizer.GetInt32());
+  // It's nice to see how the min int32 value reads in hex:
+  // That is, -1 minus the unsigned payload (0x7fffffff, see above).
+  EXPECT_EQ(-0x80000000l, tokenizer.GetInt32());
   tokenizer.Next();
   EXPECT_EQ(CBORTokenTag::DONE, tokenizer.TokenTag());
 }