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 44a3e57fcd766706493ae9d655d16262f89635e4..0a690d88c666a2b05ddfd65a5d66a270c61dbc4d 100644
--- a/Source/devtools/protocol.json
+++ b/Source/devtools/protocol.json
@@ -3281,6 +3281,14 @@
                 ],
                 "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": [