DevTools: Introduce Debugger::Reason::PromiseRejection pause reason.

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 3504 matching lines @@
                 "parameters": [
                     { "name": "breakpointId", "$ref": "BreakpointId", "description": "Breakpoint unique identifier." },
                     { "name": "location", "$ref": "Location", "description": "Actual breakpoint location." }
                 ],
                 "description": "Fired when breakpoint is resolved to an actual script and location."
             },
             {
                 "name": "paused",
                 "parameters": [
                     { "name": "callFrames", "type": "array", "items": { "$ref": "CallFrame" }, "description": "Call stack the virtual machine stopped on." },
-                    { "name": "reason", "type": "string", "enum": [ "XHR", "DOM", "EventListener", "exception", "assert", "CSPViolation", "debugCommand", "other" ], "description": "Pause reason." },
+                    { "name": "reason", "type": "string", "enum": [ "XHR", "DOM", "EventListener", "exception", "assert", "CSPViolation", "debugCommand", "promiseRejection", "other" ], "description": "Pause reason." },
                     { "name": "data", "type": "object", "optional": true, "description": "Object containing break-specific auxiliary properties." },
                     { "name": "hitBreakpoints", "type": "array", "optional": true, "items": { "type": "string" }, "description": "Hit breakpoints IDs", "hidden": true },
                     { "name": "asyncStackTrace", "$ref": "StackTrace", "optional": true, "description": "Async stack trace, if any.", "hidden": true }
                 ],
                 "description": "Fired when the virtual machine stopped on breakpoint or exception or any other stop criteria."
             },
             {
                 "name": "resumed",
                 "description": "Fired when the virtual machine resumed execution."
             }
@@ skipping 870 matching lines @@
             {
                 "name": "dataAvailable",
                 "parameters": [
                     {"name": "value", "type": "array", "items": { "$ref": "PowerEvent" }, "description": "List of power events." }
                 ],
                 "handlers": ["browser", "frontend"]
             }
         ]
     }]
 }