Issue #2053 - Part 4b: Fix measure name to timestamp conversion

Partially based on https://bugzilla.mozilla.org/show_bug.cgi?id=1772417

dom/bindings/Errors.msg

@@ -108,3 +108,4 @@ MSG_DEF(MSG_PMO_UNKNOWN_MARK_NAME, 1, JSEXN_SYNTAXERR, "Given mark name, {0}, is
 MSG_DEF(MSG_PMO_CONSTRUCTOR_INACCESSIBLE, 0, JSEXN_TYPEERR, "Can't access PerformanceMark constructor, performance is null.")
 MSG_DEF(MSG_PMO_INVALID_TIMING_ATTR, 0, JSEXN_SYNTAXERR, "markName cannot be a performance timing attribute.")
 MSG_DEF(MSG_PMO_UNEXPECTED_START_TIME, 0, JSEXN_TYPEERR, "Expected startTime >= 0.")
+MSG_DEF(MSG_PMO_INVALID_ATTR_FOR_NON_GLOBAL, 1, JSEXN_TYPEERR, "Cannot get PerformanceTiming attribute values for non-Window global object. Given: {0}.")

dom/performance/Performance.cpp

@@ -326,8 +326,11 @@ DOMHighResTimeStamp
 Performance::ConvertMarkToTimestampWithString(const nsAString& aName,
                                               ErrorResult& aRv)
 {
+  if (IsPerformanceTimingAttribute(aName)) {
+    return ConvertNameToTimestamp(aName, aRv);
+  }
+
   AutoTArray<RefPtr<PerformanceEntry>, 1> arr;
-  DOMHighResTimeStamp ts;
   Optional<nsAString> typeParam;
   nsAutoString str;
   str.AssignLiteral("mark");
@@ -337,18 +340,8 @@ Performance::ConvertMarkToTimestampWithString(const nsAString& aName,
     return arr.LastElement()->StartTime();
   }
 
-  if (!IsPerformanceTimingAttribute(aName)) {
-    aRv.ThrowTypeError<MSG_PMO_UNKNOWN_MARK_NAME>(aName);
-    return 0;
-  }
-
-  ts = GetPerformanceTimingFromString(aName);
-  if (!ts) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_ACCESS_ERR);
-    return 0;
-  }
-
-  return ts - CreationTime();
+  aRv.ThrowTypeError<MSG_PMO_UNKNOWN_MARK_NAME>(aName);
+  return 0;
 }
 
 DOMHighResTimeStamp
@@ -390,6 +383,34 @@ Performance::ConvertMarkToTimestamp(
       aAttribute, aMarkNameOrTimestamp.GetAsDouble(), aRv);
 }
 
+DOMHighResTimeStamp Performance::ConvertNameToTimestamp(const nsAString& aName,
+                                                        ErrorResult& aRv) {
+  if (!IsGlobalObjectWindow()) {
+    aRv.ThrowTypeError<MSG_PMO_INVALID_ATTR_FOR_NON_GLOBAL>(aName);
+    return 0;
+  }
+
+  if (aName.EqualsASCII("navigationStart")) {
+    return 0;
+  }
+
+  // We use GetPerformanceTimingFromString, rather than calling the
+  // navigationStart method timing function directly, because the former handles
+  // reducing precision against timing attacks.
+  const DOMHighResTimeStamp startTime =
+    GetPerformanceTimingFromString(NS_LITERAL_STRING("navigationStart"));
+  const DOMHighResTimeStamp endTime =
+    GetPerformanceTimingFromString(aName);
+  MOZ_ASSERT(endTime >= 0);
+  if (endTime == 0) {
+    // Was given a PerformanceTiming attribute which isn't available yet.
+    aRv.Throw(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+    return 0;
+  }
+
+  return endTime - startTime;
+}
+
 DOMHighResTimeStamp
 Performance::ResolveEndTimeForMeasure(
   const Optional<nsAString>& aEndMark,

dom/performance/Performance.h

@@ -190,6 +190,9 @@ private:
       const ResolveTimestampAttribute aAttribute,
       const OwningStringOrDouble& aMarkNameOrTimestamp, ErrorResult& aRv);
 
+  DOMHighResTimeStamp ConvertNameToTimestamp(const nsAString& aName,
+                                             ErrorResult& aRv);
+
   DOMHighResTimeStamp ResolveEndTimeForMeasure(
       const Optional<nsAString>& aEndMark,
       const PerformanceMeasureOptions* aOptions,