Add support for returning traces as streams in DevTools protocol

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications.",
@@ skipping 4799 matching lines @@
                     { "name": "categories", "type": "string", "optional": true, "description": "Category/tag filter" },
                     { "name": "options", "type": "string", "optional": true, "description": "Tracing options" },
                     { "name": "bufferUsageReportingInterval", "type": "number", "optional": true, "description": "If set, the agent will issue bufferUsage events at this interval, specified in milliseconds" }
                 ],
                 "handlers": ["browser", "renderer"]
             },
             {
                 "name": "end",
                 "async": true,
                 "description": "Stop trace events collection.",
+                "parameters": [
+                    { "name": "returnAsStream", "type": "boolean", "optional": true, "description": "Dump traces to a stream and resturn stream id, rather than emit dataCollected messages." }

[pfeldman, 2015/08/24 17:51:15]

I think this belongs to start.

+                ],
                 "handlers": ["browser", "renderer"]
             },
             {
                 "name": "getCategories",
                 "async": true,
                 "description": "Gets supported tracing categories.",
                 "returns": [
                     { "name": "categories", "type": "array", "items": { "type": "string" }, "description": "A list of supported tracing categories." }
                 ],
                 "handlers": ["browser"]
@@ skipping 328 matching lines @@
                 ],
                 "returns": [
                     { "name": "accessibilityNode", "$ref": "AXNode", "description": "The <code>Accessibility.AXNode</code> for this DOM node, if it exists.", "optional": true }
                 ],
                 "description": "Fetches the accessibility node for this DOM node, if it exists.",
                 "hidden": true
             }
         ]
     }]
 }