DevTools: show progress when retrieving recorded trace events

Source/devtools/front_end/sdk/TracingManager.js

Index: Source/devtools/front_end/sdk/TracingManager.js
diff --git a/Source/devtools/front_end/sdk/TracingManager.js b/Source/devtools/front_end/sdk/TracingManager.js
index 204a6edd50d6b47201d0c21c406930e0397f33b8..eb1626d070514507b00eb0feb78ca1b95495f2de 100644
--- a/Source/devtools/front_end/sdk/TracingManager.js
+++ b/Source/devtools/front_end/sdk/TracingManager.js
@@ -13,10 +13,13 @@ WebInspector.TracingManager = function()
 {
     WebInspector.Object.call(this);
     this._active = false;
+    this._eventBufferSize = 0;
+    this._eventsRetrieved = 0;
     WebInspector.targetManager.observeTargets(this);
 }
 
 WebInspector.TracingManager.Events = {
+    "RetrieveEventsProgress": "RetrieveEventsProgress",
     "BufferUsage": "BufferUsage",
     "TracingStarted": "TracingStarted",
     "EventsCollected": "EventsCollected",
@@ -70,11 +73,14 @@ WebInspector.TracingManager.prototype = {
     },
 
     /**
-     * @param {number} usage
+     * @param {number=} usage
+     * @param {number=} eventCount
+     * @param {number=} percentFull
      */
-    _bufferUsage: function(usage)
+    _bufferUsage: function(usage, eventCount, percentFull)
     {
-        this.dispatchEventToListeners(WebInspector.TracingManager.Events.BufferUsage, usage);
+        this._eventBufferSize = eventCount;
+        this.dispatchEventToListeners(WebInspector.TracingManager.Events.BufferUsage, usage || percentFull);
     },
 
     /**
@@ -83,10 +89,18 @@ WebInspector.TracingManager.prototype = {
     _eventsCollected: function(events)
     {
         this.dispatchEventToListeners(WebInspector.TracingManager.Events.EventsCollected, events);
+        this._eventsRetrieved += events.length;
+        if (!this._eventBufferSize)
+            return;
+        if (this._eventsRetrieved > this._eventBufferSize)
+            this._eventsRetrieved = this._eventBufferSize;
+        this.dispatchEventToListeners(WebInspector.TracingManager.Events.RetrieveEventsProgress, this._eventsRetrieved / this._eventBufferSize);
     },
 
     _tracingComplete: function()
     {
+        this._eventBufferSize = 0;
+        this._eventsRetrieved = 0;
         this.dispatchEventToListeners(WebInspector.TracingManager.Events.TracingComplete);
     },
 
@@ -137,11 +151,13 @@ WebInspector.TracingDispatcher = function(tracingManager)
 
 WebInspector.TracingDispatcher.prototype = {
     /**
-     * @param {number} usage
+     * @param {number=} usage
+     * @param {number=} eventCount
+     * @param {number=} percentFull
      */
-    bufferUsage: function(usage)
+    bufferUsage: function(usage, eventCount, percentFull)
     {
-        this._tracingManager._bufferUsage(usage);
+        this._tracingManager._bufferUsage(usage, eventCount, percentFull);
     },
 
     /**