DevTools: Support asynchronous call stacks on backend.

Source/devtools/protocol.json

Index: Source/devtools/protocol.json
diff --git a/Source/devtools/protocol.json b/Source/devtools/protocol.json
index ce3f8bc0118fef8c55a11c7cfeda511391b7aa89..d7da7c89b2c821e10afba4aeb3f4e70ce9a1cad8 100644
--- a/Source/devtools/protocol.json
+++ b/Source/devtools/protocol.json
@@ -2965,7 +2965,8 @@
                     { "name": "location", "$ref": "Location", "description": "Location in the source code." },
                     { "name": "scopeChain", "type": "array", "items": { "$ref": "Scope" }, "description": "Scope chain for this call frame." },
                     { "name": "this", "$ref": "Runtime.RemoteObject", "description": "<code>this</code> object for this call frame." },
-                    { "name": "returnValue", "$ref": "Runtime.RemoteObject", "optional": true, "hidden": true, "description": "The value being returned, if the function is at return point." }
+                    { "name": "returnValue", "$ref": "Runtime.RemoteObject", "optional": true, "hidden": true, "description": "The value being returned, if the function is at return point." },
+                    { "name": "asyncCallFrames", "type": "array", "items": { "$ref": "CallFrame" }, "optional": true, "hidden": true, "description": "Asynchronous call stack, if any." }
                 ],
                 "description": "JavaScript call frame. Array of call frames form the call stack."
             },
@@ -3255,6 +3256,14 @@
                 ],
                 "hidden": true,
                 "description": "Makes backend skip steps in the sources with names matching given pattern. VM will try leave blacklisted scripts by performing 'step in' several times, finally resorting to 'step out' if unsuccessful."
+            },
+            {
+                "name": "setAsyncCallStackDepth",
+                "parameters": [
+                    { "name": "maxDepth", "type": "integer", "description": "Maximum depth of async call stacks. Setting to <code>0</code> will effectively disable collecting async call stacks (default)." }
+                ],
+                "hidden": true,
+                "description": "Enables or disables async call stacks tracking."
             }
         ],
         "events": [