Add intrinsic time unit to Model.

BUG=#624
R=nduca@chromium.org

Review URL: https://codereview.appspot.com/248870043

Change-Id: I9ad83391f01d3abd74c08cea67a13c848eccffa3

trace_viewer/model/model.html

@@ -9,6 +9,7 @@
 <link rel="import" href="/base/interval_tree.html">
 <link rel="import" href="/base/range.html">
 <link rel="import" href="/base/task.html">
+<link rel="import" href="/base/units/time.html">
 <link rel="import" href="/ui/base/overlay.html">
 <link rel="import" href="/core/filter.html">
 <link rel="import" href="/core/auditor.html">
@@ -122,6 +123,7 @@
     this.instantEvents = [];
     this.flowEvents = [];
     this.clockSyncRecords = [];
+    this.intrinsicTimeUnit_ = undefined;
 
     this.stackFrames = {};
     this.samples = [];
@@ -705,6 +707,24 @@
       this.reportedImportWarnings_[data.type] = true;
     },
 
+    /**
+     * Returns a time unit that is used to format values and determines the
+     * precision of the timestamp values.
+     */
+    get intrinsicTimeUnit() {
+      if (this.intrinsicTimeUnit_ === undefined)
+        return tr.b.units.Time.supportedUnits.ms;
+      return this.intrinsicTimeUnit_;
+    },
+
+    set intrinsicTimeUnit(value) {
+      if (this.intrinsicTimeUnit_ === value)
+        return;
+      if (this.intrinsicTimeUnit_ !== undefined)
+        throw new Error('Intrinsic time unit already set');
+      this.intrinsicTimeUnit_ = value;
+    },
+
     get hasImportWarnings() {
       return (this.importWarnings_.length > 0);
     },

trace_viewer/model/model_test.html

@@ -5,6 +5,7 @@
 found in the LICENSE file.
 -->
 
+<link rel="import" href="/base/units/time.html">
 <link rel="import" href="/core/test_utils.html">
 <link rel="import" href="/extras/full_config.html">
 <link rel="import" href="/model/annotation.html">
@@ -409,5 +410,22 @@
     assert.equal(m.getAnnotationByGUID(a2.guid), a2);
     assert.equal(m.getAllAnnotations().length, 1);
   });
+
+  test('model_intrinsicTimeUnit', function() {
+    var unit = tr.b.units.Time.supportedUnits;
+    var m = new tr.Model();
+
+    // by default it should be milliseconds
+    assert.equal(m.intrinsicTimeUnit, unit.ms);
+
+    m.intrinsicTimeUnit = unit.ns;
+    assert.equal(m.intrinsicTimeUnit, unit.ns);
+    // should be able to set to the same
+    m.intrinsicTimeUnit = unit.ns;
+    assert.equal(m.intrinsicTimeUnit, unit.ns);
+    // should not be able to change it after fixing it
+    assert.throw(function() { m.intrinsicTimeUnit = unit.ms; });
+    assert.equal(m.intrinsicTimeUnit, unit.ns);
+  });
 });
 </script>