Fix encoding handling on decode of inspector state 8-bit strings

The marshalling code writes out utf-8, but demarshalling used WTFString
ctor which is latin1

Bug: 1161142
Change-Id: I55c4f5a38d76ff6f6c6e502e6a84471327de37d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2602360
Commit-Queue: Maksim Orlovich <morlovich@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841510}

third_party/blink/renderer/core/inspector/inspector_session_state.cc

@@ -128,7 +128,7 @@ void InspectorAgentState::Serialize(const WTF::String& v,
 bool InspectorAgentState::Deserialize(span<uint8_t> in, WTF::String* v) {
   CBORTokenizer tokenizer(in);
   if (tokenizer.TokenTag() == CBORTokenTag::STRING8) {
-    *v = WTF::String(
+    *v = WTF::String::FromUTF8(
         reinterpret_cast<const char*>(tokenizer.GetString8().data()),
         static_cast<size_t>(tokenizer.GetString8().size()));
     return true;

third_party/blink/renderer/core/inspector/inspector_session_state_test.cc

@@ -82,10 +82,14 @@ TEST(InspectorSessionStateTest, SimpleFields) {
     simple_agent.counter_.Set(311);
     simple_agent.bytes_.Set({0xde, 0xad, 0xbe, 0xef});
 
+    // Test that Latin1 is handled properly
+    simple_agent.message_.Set("\xC7 cedilla");
+
     EXPECT_EQ(true, simple_agent.enabled_.Get());
     EXPECT_EQ(11.0, simple_agent.field1_.Get());
     EXPECT_EQ(42.0, simple_agent.multiplier_.Get());
     EXPECT_EQ(311, simple_agent.counter_.Get());
+    EXPECT_EQ("\xC7 cedilla", simple_agent.message_.Get());
     EXPECT_THAT(simple_agent.bytes_.Get(), ElementsAre(0xde, 0xad, 0xbe, 0xef));
 
     // Now send the updates back to the browser session.
@@ -101,6 +105,7 @@ TEST(InspectorSessionStateTest, SimpleFields) {
     EXPECT_EQ(11.0, simple_agent.field1_.Get());
     EXPECT_EQ(42.0, simple_agent.multiplier_.Get());
     EXPECT_EQ(311, simple_agent.counter_.Get());
+    EXPECT_EQ("\xC7 cedilla", simple_agent.message_.Get());
     EXPECT_THAT(simple_agent.bytes_.Get(), ElementsAre(0xde, 0xad, 0xbe, 0xef));
 
     simple_agent.enabled_.Set(false);