DevTools: Support asynchronous call stacks on backend.

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 2940 matching lines @@
             },
             {
                 "id": "CallFrame",
                 "type": "object",
                 "properties": [
                     { "name": "callFrameId", "$ref": "CallFrameId", "description": "Call frame identifier. This identifier is only valid while the virtual machine is paused." },
                     { "name": "functionName", "type": "string", "description": "Name of the JavaScript function called on this call frame." },
                     { "name": "location", "$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." }

[yurys, 2013/11/20 14:07:57]

Why is it property on CallFrame, I believe it should be another parameter on
"paused" event.

[aandrey, 2013/11/20 15:20:02]

Here is the list of commands and events that return debugger callFrames:

Debugger.setScriptSource
Debugger.restartFrame
Debugger.getBacktrace
Debugger.paused

In all of them we'd like to send async stacks.

Besides, should you want to return it separately, it will be of type
{Array.<Array.<CallFrame>>} - quite complex and I doubt our code generator
supports this at the moment.

Ideally we should have created a Debugger.StackTrace class as we did for the
Console.StackTrace. If we had done it, this is where the async call frames would
live.

To preserve the backward compatibility, this is the best solution I could think
of.

[yurys, 2013/11/28 10:35:41]

I'd rather add explicit async call stack property there. asyncCallFrames
property on CallFrame looks very confusing.
To preserve backward compatibility you could use Debugger.StackTrace for async
call stacks only.

                 ],
                 "description": "JavaScript call frame. Array of call frames form the call stack."
             },
             {
                 "id": "Scope",
                 "type": "object",
                 "properties": [
                     { "name": "type", "type": "string", "enum": ["global", "local", "with", "closure", "catch"], "description": "Scope type." },
                     { "name": "object", "$ref": "Runtime.RemoteObject", "description": "Object representing the scope. For <code>global</code> and <code>with</code> scopes it represents the actual object; for the rest of the scopes, it is artificial transient object enumerating scope variables as its properties." }
                 ],
@@ skipping 269 matching lines @@
                 "hidden": true,
                 "description": "Returns call stack including variables changed since VM was paused. VM must be paused."
             },
             {
                 "name": "skipStackFrames",
                 "parameters": [
                     { "name": "script", "optional": true, "type": "string", "description": "Regular expression defining the scripts to ignore while stepping." }
                 ],
                 "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": "enableAsyncCallStacks",

[yurys, 2013/11/20 01:23:43]

setAsyncCallStackDepth?

[aandrey, 2013/11/20 15:20:02]

Done.

+                "parameters": [
+                    { "name": "maxDepth", "type": "integer", "description": "Maximum depth of async call stacks. Setting <code>0</code> will effectively disable async call stacks (default)." }
+                ],
+                "hidden": true,
+                "description": "Enables or disables async call stacks tracking."
             }
         ],
         "events": [
             {
                 "name": "globalObjectCleared",
                 "description": "Called when global has been cleared and debugger client should reset its state. Happens upon navigation or reload."
             },
             {
                 "name": "scriptParsed",
                 "parameters": [
@@ skipping 776 matching lines @@
                 "parameters": [
                     { "name": "value", "type": "array", "items": { "type": "object" } }
                 ]
             },
             {
                 "name": "tracingComplete"
             }
         ]
     }]
 }