--- a/dom/chrome-webidl/ChromeUtils.webidl
+++ b/dom/chrome-webidl/ChromeUtils.webidl
@@ -549,17 +549,17 @@ dictionary ChildProcInfoDictionary {
   long long pid = 0;
   DOMString filename = "";
   unsigned long long virtualMemorySize = 0;
   long long residentSetSize = 0;
   unsigned long long cpuUser = 0;
   unsigned long long cpuKernel = 0;
   sequence<ThreadInfoDictionary> threads = [];
   // Firefox info
-  unsigned long long ChildID = 0;
+  unsigned long long childID = 0;
   UTF8String origin = "";
   WebIDLProcType type = "web";
 };
 
 dictionary ParentProcInfoDictionary {
   // System info
   long long pid = 0;
   DOMString filename = "";

--- a/widget/tests/browser/browser_test_procinfo.js
+++ b/widget/tests/browser/browser_test_procinfo.js
@@ -44,16 +44,26 @@ add_task(async function test_proc_info()
 
         for (var i = 0; i < parentProc.children.length; i++) {
           let childProc = parentProc.children[i];
           Assert.notEqual(
             childProc.type,
             "browser",
             "Child proc type should not be browser"
           );
+          if (
+            childProc.type.startsWith("web") ||
+            childProc.type.startsWith("Web")
+          ) {
+            Assert.notEqual(
+              childProc.childID,
+              0,
+              "Child proc should not have a 0 childID"
+            );
+          }
           Assert.notEqual(
             childProc.type,
             "unknown",
             "Child proc type should be known"
           );
           if (childProc.type == "webIsolated") {
             Assert.notEqual(
               childProc.origin || "",