Implements extensions devtools API

chrome/test/data/extensions/devtools/timeline_api_two/background_two.html

Index: chrome/test/data/extensions/devtools/timeline_api_two/background_two.html
diff --git a/chrome/test/data/extensions/devtools/timeline_api_two/background_two.html b/chrome/test/data/extensions/devtools/timeline_api_two/background_two.html
new file mode 100644
index 0000000000000000000000000000000000000000..fa0422e795ec8ba9b3a9682da05b9598ff935f60
--- /dev/null
+++ b/chrome/test/data/extensions/devtools/timeline_api_two/background_two.html
@@ -0,0 +1,32 @@
+<script>
+
+var devtoolsTabEvents = undefined;
+
+function tabUrlChangeListener() {
+  receivedEvents.push("onTabUrlChange");
+}
+
+function pageEventListener() {
+  receivedEvents.push("onPageEvent");
+}
+
+function tabCloseListener() {
+  receivedEvents.push("onTabClose");
+}
+
+function registerListenersForTab(tabId) {
+  devtoolsTabEvents = chrome.devtools.getTabEvents(tabId);
+  devtoolsTabEvents.onPageEvent.addListener(pageEventListener);
+  devtoolsTabEvents.onTabUrlChange.addListener(tabUrlChangeListener);
+  devtoolsTabEvents.onTabClose.addListener(tabCloseListener);
+  window.domAutomationController.send(true);
+}
+
+function unregisterListeners() {
+  devtoolsTabEvents.onPageEvent.removeListener(pageEventListener);
+  devtoolsTabEvents.onTabUrlChange.removeListener(tabUrlChangeListener);
+  devtoolsTabEvents.onTabClose.removeListener(tabCloseListener);
+  window.domAutomationController.send(true);
+}
+
+</script>