Hide cold mode idle time spellchecker behind a flag

third_party/WebKit/Source/platform/RuntimeEnabledFeatures.json5

 {
   // http://dev.chromium.org/blink/runtime-enabled-features
   //
   // This list is used to generate RuntimeEnabledFeatures.h/cpp which contains
   // a class that stores static enablers for all experimental features.
 
   parameters: {
     // Each feature can be assigned a "status":
     // status=stable -> Enable this in all Blink configurations.  We are committed to these APIs indefinitely.
     // status=experimental -> In-progress features, Web Developers might play with, but are not on by default in stable.
@@ skipping 476 matching lines @@
     },
     {
       name: "HideNonceContentAttribute",
       status: "experimental",
     },
     {
       name: "IDBObserver",
       status: "experimental",
     },
     {
+      name: "IdleTimeColdModeSpellChecking",

[yosin_UTC9, 2017/04/20 01:10:45]

Is it better to have a comment that IdleTimeColdModeSpeillChecking will work if
IdleTimeSpellChecking enabled?

[Xiaocheng, 2017/04/20 01:40:09]

I think there's no need to add a comment that says the same thing as the code...

+      depends_on: ["IdleTimeSpellChecking"],
+      status: "test",
+    },
+    {
       name: "IdleTimeSpellChecking",
       status: "test",
     },
     {
       name: "ImageCapture",
       status: "stable",
     },
     {
       name: "ImageOrientation",
       status: "test",
@@ skipping 535 matching lines @@
     {
       name: "Worklet",
       status: "experimental",
     },
     {
       name: "XSLT",
       status: "stable",
     },
   ],
 }