Tab Search: Add metrics to track switched tab position

This CL adds metrics to track the position of a switched tab from
both filtered and unfiltered lists.

Bug: 1099917
Change-Id: I4cb7822240bd78b228906b0fd86eaf364b4cdb33
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2529692
Commit-Queue: Thomas Lukaszewicz <tluk@chromium.org>
Reviewed-by: Yuheng Huang <yuhengh@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826869}

chrome/browser/resources/tab_search/app.js

@@ -281,8 +281,9 @@ export class TabSearchAppElement extends PolymerElement {
    * @private
    */
   onItemClick_(e) {
+    const tabIndex = e.currentTarget.parentNode.indexOf(e.currentTarget);
     const tabId = Number.parseInt(e.currentTarget.id, 10);
-    this.apiProxy_.switchToTab({tabId}, !!this.searchText_);
+    this.apiProxy_.switchToTab({tabId}, !!this.searchText_, tabIndex);
   }
 
   /**
@@ -371,7 +372,8 @@ export class TabSearchAppElement extends PolymerElement {
       e.preventDefault();
     } else if (e.key === 'Enter' || e.key === ' ') {
       this.apiProxy_.switchToTab(
-          {tabId: this.getSelectedTab_().tabId}, !!this.searchText_);
+          {tabId: this.getSelectedTab_().tabId}, !!this.searchText_,
+          this.getSelectedIndex());
       e.stopPropagation();
     }
   }
@@ -424,7 +426,8 @@ export class TabSearchAppElement extends PolymerElement {
           this.ariaLabel_(this.filteredOpenTabs_[this.getSelectedIndex()]));
     } else if (e.key === 'Enter') {
       this.apiProxy_.switchToTab(
-          {tabId: this.getSelectedTab_().tabId}, !!this.searchText_);
+          {tabId: this.getSelectedTab_().tabId}, !!this.searchText_,
+          this.getSelectedIndex());
       e.stopPropagation();
     }
   }

chrome/browser/resources/tab_search/tab_search_api_proxy.js

@@ -29,8 +29,9 @@ export class TabSearchApiProxy {
   /**
    * @param {!SwitchToTabInfo} info
    * @param {boolean} withSearch
+   * @param {number} switchedTabIndex
    */
-  switchToTab(info, withSearch) {}
+  switchToTab(info, withSearch, switchedTabIndex) {}
 
   /** @return {!PageCallbackRouter} */
   getCallbackRouter() {}
@@ -71,12 +72,17 @@ export class TabSearchApiProxyImpl {
   }
 
   /** @override */
-  switchToTab(info, withSearch) {
+  switchToTab(info, withSearch, switchedTabIndex) {
     chrome.metricsPrivate.recordEnumerationValue(
         'Tabs.TabSearch.WebUI.TabSwitchAction',
         withSearch ? TabSwitchAction.WITH_SEARCH
                    : TabSwitchAction.WITHOUT_SEARCH,
         Object.keys(TabSwitchAction).length);
+    chrome.metricsPrivate.recordSmallCount(
+        withSearch ? 'Tabs.TabSearch.WebUI.IndexOfSwitchTabInFilteredList' :
+                     'Tabs.TabSearch.WebUI.IndexOfSwitchTabInUnfilteredList',
+        switchedTabIndex);
+
     this.handler.switchToTab(info);
   }
 

chrome/test/data/webui/tab_search/tab_search_app_test.js

@@ -286,9 +286,24 @@ suite('TabSearchAppTest', () => {
 
     // Assert switchToTab() was called appropriately for an unfiltered tab list.
     await testProxy.whenCalled('switchToTab')
-        .then(([ tabInfo, withSearch ]) => {
+        .then(([tabInfo, withSearch, switchedTabIndex]) => {
           assertEquals(1, tabInfo.tabId);
           assertFalse(withSearch);
+          assertEquals(0, switchedTabIndex);
+        });
+
+    testProxy.reset();
+    // Click the first element with tabId 6.
+    tabSearchItem = /** @type {!HTMLElement} */
+        (tabSearchApp.shadowRoot.querySelector('tab-search-item[id="6"]'));
+    tabSearchItem.click();
+
+    // Assert switchToTab() was called appropriately for an unfiltered tab list.
+    await testProxy.whenCalled('switchToTab')
+        .then(([tabInfo, withSearch, switchedTabIndex]) => {
+          assertEquals(6, tabInfo.tabId);
+          assertFalse(withSearch);
+          assertEquals(2, switchedTabIndex);
         });
 
     // Force a change to filtered tab data that would result in a
@@ -308,9 +323,10 @@ suite('TabSearchAppTest', () => {
     // Assert switchToTab() was called appropriately for a tab list fitlered by
     // the search query.
     await testProxy.whenCalled('switchToTab')
-        .then(([ tabInfo, withSearch ]) => {
+        .then(([tabInfo, withSearch, switchedTabIndex]) => {
           assertEquals(2, tabInfo.tabId);
           assertTrue(withSearch);
+          assertEquals(0, switchedTabIndex);
         });
   });
 

chrome/test/data/webui/tab_search/test_tab_search_api_proxy.js

@@ -46,8 +46,8 @@ export class TestTabSearchApiProxy extends TestBrowserProxy {
   }
 
   /** @override */
-  switchToTab(tabInfo, withSearch) {
-    this.methodCalled('switchToTab', [ tabInfo, withSearch ]);
+  switchToTab(tabInfo, withSearch, switchedTabIndex) {
+    this.methodCalled('switchToTab', [tabInfo, withSearch, switchedTabIndex]);
   }
 
   /** @override */

tools/metrics/histograms/histograms_xml/tab/histograms.xml

@@ -2048,6 +2048,29 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="Tabs.TabSearch.WebUI.IndexOf{Action}TabIn{State}List"
+    units="tabs" expires_after="M90">
+  <owner>tluk@chromium.org</owner>
+  <owner>robliao@chromium.org</owner>
+  <owner>yuhengh@chromium.org</owner>
+  <owner>romanarora@chromium.org</owner>
+  <summary>
+    Tab Search is a feature that allows users to better search their browsers
+    for their desired tabs and close any currently open tabs.
+
+    This records the index at which a {Action} has been performed on a tab in
+    Tab Search's tab list in a {State} state.
+  </summary>
+  <token key="Action">
+    <variant name="Close"/>
+    <variant name="Switch"/>
+  </token>
+  <token key="State">
+    <variant name="Filtered" summary="Filtered by user search query."/>
+    <variant name="Unfiltered" summary="Unfiltered by user search query."/>
+  </token>
+</histogram>
+
 <histogram name="Tabs.TabSearch.WebUI.InitialTabsRenderTime" units="ms"
     expires_after="M90">
   <owner>tluk@chromium.org</owner>