[M115] Use camelCase for enableDebugMode's debug key argument

i.e. debug_key -> debugKey. This would align with the web platform
design principles: https://www.w3.org/TR/design-principles/#casing-rules

Note that this does not change the JSON key used in the eventual report.
This change is breaking, but code can be written to support both pre-
and post-fix browsers to avoid compatibility issues, e.g.:
```
privateAggregation.enableDebugMode({debug_key: 123n, debugKey: 123n});
```

(cherry picked from commit c542499)

Bug: 1416320
Change-Id: I87413ccccab985e784fe8c87c86acf7435307f3c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4264741
Reviewed-by: Russ Hamilton <behamilton@google.com>
Commit-Queue: Alex Turner <alexmt@chromium.org>
Reviewed-by: Yao Xiao <yaoxia@chromium.org>
Reviewed-by: Nan Lin <linnan@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1149858}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4574539
Reviewed-by: Caleb Raitto <caraitto@chromium.org>
Reviewed-by: Cammie Smith Barnes <cammie@chromium.org>
Cr-Commit-Position: refs/branch-heads/5790@{#144}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

content/services/auction_worklet/bidder_worklet_unittest.cc

@@ -6909,7 +6909,7 @@ TEST_F(BidderWorkletPrivateAggregationEnabledTest, GenerateBid) {
         CreateGenerateBidScript(
             R"({ad: "ad", bid:1, render:"https://response.test/" })",
             /*extra_code=*/R"(
-            privateAggregation.enableDebugMode({debug_key: 1234n});
+            privateAggregation.enableDebugMode({debugKey: 1234n});
             privateAggregation.contributeToHistogram({bucket: 123n, value: 45});
             privateAggregation.contributeToHistogramOnEvent(
                 "reserved.win", {bucket: 234n, value: 56});
@@ -7201,7 +7201,7 @@ TEST_F(BidderWorkletPrivateAggregationEnabledTest, ReportWin) {
 
     RunReportWinWithFunctionBodyExpectingResult(
         R"(
-            privateAggregation.enableDebugMode({debug_key: 1234n});
+            privateAggregation.enableDebugMode({debugKey: 1234n});
             privateAggregation.contributeToHistogram({bucket: 123n, value: 45});
             privateAggregation.contributeToHistogramOnEvent(
                 "reserved.win", {bucket: 234n, value: 56});

content/services/auction_worklet/context_recycler_unittest.cc

@@ -1272,7 +1272,7 @@ class ContextRecyclerPrivateAggregationEnabledTest
   template <typename T>
   v8::Local<v8::Value> WrapDebugKey(T debug_key) {
     gin::Dictionary dict = gin::Dictionary::CreateEmpty(helper_->isolate());
-    dict.Set("debug_key", debug_key);
+    dict.Set("debugKey", debug_key);
     return gin::ConvertToV8(helper_->isolate(), dict);
   }
 
@@ -1671,8 +1671,8 @@ TEST_F(ContextRecyclerPrivateAggregationEnabledTest,
 
       // Passing BigInts in directly is complicated so we construct them from
       // strings.
-      if (typeof arg.debug_key === "string") {
-        arg.debug_key = BigInt(arg.debug_key);
+      if (typeof arg.debugKey === "string") {
+        arg.debugKey = BigInt(arg.debugKey);
       }
       privateAggregation.enableDebugMode(arg);
     }
@@ -1800,7 +1800,7 @@ TEST_F(ContextRecyclerPrivateAggregationEnabledTest,
     EXPECT_THAT(
         error_msgs,
         ElementsAre("https://example.org/script.js:21 Uncaught TypeError: "
-                    "debug_key must be a BigInt."));
+                    "debugKey must be a BigInt."));
 
     EXPECT_TRUE(context_recycler.private_aggregation_bindings()
                     ->TakePrivateAggregationRequests()

content/services/auction_worklet/seller_worklet_unittest.cc

@@ -4744,7 +4744,7 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ScoreAd) {
     RunScoreAdWithJavascriptExpectingResult(
         CreateScoreAdScript("5",
                             R"(
-            privateAggregation.enableDebugMode({debug_key: 1234n});
+            privateAggregation.enableDebugMode({debugKey: 1234n});
             privateAggregation.contributeToHistogram({bucket: 123n, value: 45});
             privateAggregation.contributeToHistogramOnEvent(
               "reserved.win", {bucket: 234n, value: 56});
@@ -4973,7 +4973,7 @@ TEST_F(SellerWorkletPrivateAggregationEnabledTest, ReportResult) {
     RunReportResultCreatedScriptExpectingResult(
         "5",
         R"(
-            privateAggregation.enableDebugMode({debug_key: 1234n});
+            privateAggregation.enableDebugMode({debugKey: 1234n});
             privateAggregation.contributeToHistogram({bucket: 123n, value: 45});
         )",
         /*expected_signals_for_winner=*/"5",

content/services/worklet_utils/private_aggregation_utils.cc

@@ -67,7 +67,7 @@ absl::optional<uint64_t> ParseDebugKey(v8::Local<v8::Value> js_debug_key,
     return absl::Uint128Low64(maybe_debug_key.value());
   }
 
-  *error_out = "debug_key must be a BigInt";
+  *error_out = "debugKey must be a BigInt";
   return absl::nullopt;
 }
 
@@ -228,7 +228,8 @@ void ParseAndApplyEnableDebugModeArguments(
     }
 
     v8::Local<v8::Value> js_debug_key;
-    if (!dict.Get("debug_key", &js_debug_key)) {
+
+    if (!dict.Get("debugKey", &js_debug_key)) {
       // Propagate any exception
       return;
     }

third_party/blink/renderer/modules/shared_storage/private_aggregation.cc

@@ -150,7 +150,7 @@ void PrivateAggregation::enableDebugMode(
     if (!maybe_debug_key || absl::Uint128High64(maybe_debug_key.value()) != 0) {
       exception_state.ThrowDOMException(
           DOMExceptionCode::kDataError,
-          "options['debug_key'] is negative or does not fit in 64 bits");
+          "options['debugKey'] is negative or does not fit in 64 bits");
       return;
     }
 

third_party/blink/renderer/modules/shared_storage/private_aggregation_debug_mode_options.idl

@@ -3,5 +3,5 @@
 // found in the LICENSE file.
 
 dictionary PrivateAggregationDebugModeOptions {
-  required bigint debug_key;
+  required bigint debugKey;
 };

third_party/blink/renderer/modules/shared_storage/shared_storage_worklet_unittest.cc

@@ -2962,7 +2962,7 @@ TEST_F(SharedStoragePrivateAggregationTest,
       R"(
         let error;
         try {
-          privateAggregation.enableDebugMode({debug_key: 1234n});
+          privateAggregation.enableDebugMode({debugKey: 1234n});
           privateAggregation.enableDebugMode();
         } catch (e) {
           error = e;
@@ -2994,7 +2994,7 @@ TEST_F(SharedStoragePrivateAggregationTest,
 
       class EnableDebugMode {
         async run() {
-          privateAggregation.enableDebugMode({debug_key: 1234n});
+          privateAggregation.enableDebugMode({debugKey: 1234n});
         }
       }
 
@@ -3032,7 +3032,7 @@ TEST_F(SharedStoragePrivateAggregationTest, MultipleDebugModeRequests) {
   AddModuleResult add_module_result = AddModule(/*script_content=*/R"(
       class TestClass {
         async run() {
-          privateAggregation.enableDebugMode({debug_key: 1234n});
+          privateAggregation.enableDebugMode({debugKey: 1234n});
           privateAggregation.contributeToHistogram({bucket: 1n, value: 2});
           privateAggregation.contributeToHistogram({bucket: 3n, value: 4});
         }