Update DevTools Tracing.Start to accept trace config as a parameter

third_party/WebKit/Source/devtools/protocol.json

Index: third_party/WebKit/Source/devtools/protocol.json
diff --git a/third_party/WebKit/Source/devtools/protocol.json b/third_party/WebKit/Source/devtools/protocol.json
index 8ca06b8440503febf231b190c57ba0883171813b..964cd2c5c0277ea12710f0b04a9752a723e4098e 100644
--- a/third_party/WebKit/Source/devtools/protocol.json
+++ b/third_party/WebKit/Source/devtools/protocol.json
@@ -4824,16 +4824,62 @@
     },
     {
         "domain": "Tracing",
+        "types": [
+            {
+                "id": "RecordMode",

[pfeldman, 2016/03/15 18:03:53]

Inline enum, call property "bufferType".

[Zhen Wang, 2016/03/17 03:58:14]

Done.

+                "type": "string",
+                "enum": ["recordUntilFull", "recordContinuously", "recordAsMuchAsPossible", "echoToConsole"],
+                "description": "Option that determines how the trace buffer stores data."
+            },
+            {
+                "id": "MemoryDumpTriggerMode",

[pfeldman, 2016/03/15 18:03:53]

Inline enum.

[Zhen Wang, 2016/03/17 03:58:14]

Done.

+                "type": "string",
+                "enum": ["light", "detailed"],
+                "description": "Level of detail of the triggered memory dumps."
+            },
+            {
+                "id": "MemoryDumpTrigger",
+                "type": "object",
+                "properties": [
+                    { "name": "mode", "$ref": "MemoryDumpTriggerMode", "optional": false, "description": "Level of detail of the triggered memory dumps." },

[pfeldman, 2016/03/15 18:03:53]

remove "optional": false.

[Zhen Wang, 2016/03/17 03:58:15]

Done.

+                    { "name": "periodicIntervalMs", "type": "integer", "optional": false, "description": "Length of the periodic intervals between the triggered memory dumps." }

[pfeldman, 2016/03/15 18:03:53]

Everything is ms, this could be called "interval".

[pfeldman, 2016/03/15 18:03:53]

ditto

+                ],
+                "description": "Memory dump trigger configuration."
+            },
+            {
+                "id": "MemoryDumpConfig",
+                "type": "object",
+                "properties": [
+                    { "name": "triggers", "type": "array", "items": { "$ref": "MemoryDumpTrigger" }, "optional": false, "description": "Memory dump trigger configuration." }

[pfeldman, 2016/03/15 18:03:53]

So we have an array of triggers, but they only carry "mode" and "interval". Are
you defining an interval for "light" and an interval for "detailed"? I.e. array
is up to two items until you get more modes?

[Zhen Wang, 2016/03/17 03:58:15]

Currently there are only two items by default. I think it could be more in the
future.

+                ],
+                "description": "Configuration for memory dump triggers. Used only when \"memory-infra\" category is enabled."
+            },
+            {
+                "id": "TraceConfig",
+                "type": "object",
+                "properties": [
+                    { "name": "recordMode", "$ref": "RecordMode", "optional": true, "description": "Controls how the trace buffer stores data." },

[pfeldman, 2016/03/15 18:03:53]

bufferType ?

+                    { "name": "enableSampling", "type": "boolean", "optional": true, "description": "Turns on JavaScript stack sampling." },

[pfeldman, 2016/03/15 18:03:53]

Should we get an array of "features" you'd like enabled to make it more
scaleable? 

agents: ["systrace", "sampling", etc.] so that you could easily add more and
conditionally trigger them?

i.e. array of enum.

+                    { "name": "enableSystrace", "type": "boolean", "optional": true, "description": "Turns on system tracing." },
+                    { "name": "enableArgumentFilter", "type": "boolean", "optional": true, "description": "Turns on argument filter." },
+                    { "name": "includedCategories", "type": "array", "items": { "type": "string" }, "optional": true, "description": "Included category filters." },

[pfeldman, 2016/03/15 18:03:53]

"include" and "exclude" ? 

+                    { "name": "excludedCategories", "type": "array", "items": { "type": "string" }, "optional": true, "description": "Excluded category filters." },
+                    { "name": "syntheticDelays", "type": "array", "items": { "type": "string" }, "optional": true, "description": "Configuration to synthesize the delays in tracing." },

[pfeldman, 2016/03/15 18:03:53]

What does this do? Can it be computed on the client side?

[Zhen Wang, 2016/03/17 03:58:15]

This simulates additional delays in the browser for the specified trace events. 

+                    { "name": "memoryDumpConfig", "$ref": "MemoryDumpConfig", "optional": true, "description": "Configuration for memory dump triggers. Used only when \"memory-infra\" category is enabled." }

[pfeldman, 2016/03/15 18:03:53]

memory.

+                ]
+            }
+        ],
         "commands": [
             {
                 "name": "start",
                 "async": true,
                 "description": "Start trace events collection.",
                 "parameters": [
-                    { "name": "categories", "type": "string", "optional": true, "description": "Category/tag filter" },
-                    { "name": "options", "type": "string", "optional": true, "description": "Tracing options" },
+                    { "name": "categories", "type": "string", "optional": true, "deprecated": true, "description": "Category/tag filter" },
+                    { "name": "options", "type": "string", "optional": true, "deprecated": 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" },
-                    { "name": "transferMode", "type": "string", "enum": ["ReportEvents", "ReturnAsStream"], "optional": true, "description": "Whether to report trace events as series of dataCollected events or to save trace to a stream (defaults to <code>ReportEvents</code>)." }
+                    { "name": "transferMode", "type": "string", "enum": ["ReportEvents", "ReturnAsStream"], "optional": true, "description": "Whether to report trace events as series of dataCollected events or to save trace to a stream (defaults to <code>ReportEvents</code>)." },
+                    { "name": "traceConfig", "$ref": "TraceConfig", "optional": true, "description": "" }
                 ],
                 "handlers": ["browser", "renderer"]
             },