about:gpu support for thread name metadata.

chrome/browser/resources/gpu_internals/timeline_model.js

Index: chrome/browser/resources/gpu_internals/timeline_model.js
diff --git a/chrome/browser/resources/gpu_internals/timeline_model.js b/chrome/browser/resources/gpu_internals/timeline_model.js
index 1739e3c195685dc44f5c6434c218a9145a2c5774..24fa67b7fe2ce06b4c747700d91cca7d92f9c6ef 100644
--- a/chrome/browser/resources/gpu_internals/timeline_model.js
+++ b/chrome/browser/resources/gpu_internals/timeline_model.js
@@ -65,6 +65,8 @@ cr.define('gpu', function() {
   }
 
   TimelineThread.prototype = {
+    name: undefined,
+
     getSubrow: function(i) {
       while (i >= this.subRows.length)
         this.subRows.push([]);
@@ -229,12 +231,19 @@ cr.define('gpu', function() {
         } else if (event.ph == 'I') {
           // TODO(nduca): Implement parsing of immediate events.
           console.log('Parsing of I-type events not implemented.');
+        } else if (event.ph == 'M') {
+          if (event.name == 'thread_name') {
+            var thread = this.getProcess(event.pid).getThread(event.tid);
+            thread.name = event.args.name;
+          } else {
+            console.log('Unrecognized metadata name: ' + event.name);
+          }
         } else {
-          throw new Error('Unrecognized event phase: ' + event.ph +
+          console.log('Unrecognized event phase: ' + event.ph +
                           '(' + event.name + ')');
         }
       }
-
+      this.pruneEmptyThreads();
       this.updateBounds();
 
       // Add end events for any events that are still on the stack. These
@@ -268,6 +277,19 @@ cr.define('gpu', function() {
       this.maxTimestamp = this.maxTimestamp + boost;
     },
 
+    pruneEmptyThreads: function() {
+      for (var pid in this.processes) {
+        var process = this.processes[pid];
+        var prunedThreads = [];
+        for (var tid in process.threads) {
+          var thread = process.threads[tid];
+          if (thread.subRows[0].length)
+            prunedThreads.push(thread);
+        }
+        process.threads = prunedThreads;
+      }
+    },
+
     updateBounds: function() {
       var wmin = Infinity;
       var wmax = -wmin;
@@ -275,7 +297,8 @@ cr.define('gpu', function() {
       for (var tI = 0; tI < threads.length; tI++) {
         var thread = threads[tI];
         thread.updateBounds();
-        if (thread.minTimestamp && thread.maxTimestamp) {
+        if (thread.minTimestamp != undefined &&
+            thread.maxTimestamp != undefined) {
           wmin = Math.min(wmin, thread.minTimestamp);
           wmax = Math.max(wmax, thread.maxTimestamp);
         }