Set `composed: true` on all bubbled events

In Polymer 2, and when using native shadow DOM, events that do not have
`composed: true` set do not cross shadow DOM boundaries. I cross checked
and all these events seem to be handled outside of the component that
fires them, so they need this.

Change-Id: Iee8d2d545f3b1ea0bfb624648637fd190b952feb
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
index 7466ade..d27a0e5 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
@@ -269,7 +269,7 @@
     suite('render reporting', () => {
       test('starts total and content timer on render-start', done => {
         element.dispatchEvent(
-            new CustomEvent('render-start', {bubbles: true}));
+            new CustomEvent('render-start', {bubbles: true, composed: true}));
         assert.isTrue(element.$.reporting.time.calledWithExactly(
             'Diff Total Render'));
         assert.isTrue(element.$.reporting.time.calledWithExactly(
@@ -279,7 +279,7 @@
 
       test('ends content and starts syntax timer on render-content', done => {
         element.dispatchEvent(
-            new CustomEvent('render-content', {bubbles: true}));
+            new CustomEvent('render-content', {bubbles: true, composed: true}));
         assert.isTrue(element.$.reporting.time.calledWithExactly(
             'Diff Syntax Render'));
         assert.isTrue(element.$.reporting.timeEnd.calledWithExactly(
@@ -289,7 +289,7 @@
 
       test('ends total and syntax timer on render-syntax', done => {
         element.dispatchEvent(
-            new CustomEvent('render-syntax', {bubbles: true}));
+            new CustomEvent('render-syntax', {bubbles: true, composed: true}));
         assert.isTrue(element.$.reporting.timeEnd.calledWithExactly(
             'Diff Total Render'));
         assert.isTrue(element.$.reporting.timeEnd.calledWithExactly(