Dashboard - Populate bug_id with uri parameter if available.

dashboard/dashboard/elements/chart-container-test.html

Index: dashboard/dashboard/elements/chart-container-test.html
diff --git a/dashboard/dashboard/elements/chart-container-test.html b/dashboard/dashboard/elements/chart-container-test.html
index 8c4c8387ec590a0dc3fea28bebb06fee34642bf3..bfc68bb416b3f6a141a871a0ccfd229d48e7368d 100644
--- a/dashboard/dashboard/elements/chart-container-test.html
+++ b/dashboard/dashboard/elements/chart-container-test.html
@@ -105,6 +105,33 @@ tr.b.unittest.testSuite(function() {
         'http___dromaeo.com?dom-attr');
   }, testOptions);
 
+  let originalUriGetQueryString;
+  const testOptionsUri = {
+    setUp() {
+      originalUriGetQueryString = uri.getQueryString;
+    },
+    tearDown() {
+      testing_common.clearXhrMock();
+      testing_common.clearFixture();
+      uri.getQueryString = originalUriGetQueryString;
+    }
+  };
+
+  test('showTooltip uses uri bug_id', function() {
+    uri.getQueryString = function() { return '?bug_id=123'; };
+
+    testing_common.mockChartJson(
+        dromaeoCharts, dromaeoCharts.graphSelectedJson);
+    testing_common.mockChartJson(
+        sunspiderCharts, sunspiderCharts.graphSelectedJson);
+    const chart = createChart();
+    this.addHTMLOutput(chart);
+    chart.addSeriesGroup(dromaeoCharts.graphParams);
+    chart.addSeriesGroup(sunspiderCharts.graphParams);
+    chart.showTooltip(0, 0);
+    assert.strictEqual(chart.$.tooltip.bugId, '123');
+  }, testOptionsUri);
+
   test('populateTestPicker', function() {
     testing_common.mockChartJson(dromaeoCharts);
     const chart = createChart();