WebUI Tab Strip: Remove MRU sort order model

Bug: 989131
Change-Id: Ieeabc7f8ca34c7251955f9500b53e1d18bc2266c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935040
Commit-Queue: John Lee <johntlee@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719305}

chrome/browser/resources/tab_strip/tab_list.html

@@ -51,10 +51,6 @@
 <div id="tabsContainer"></div>
 
 <div id="demoOptions">
-  <label>
-    <input type="checkbox" id="mruCheckbox">MRU model
-  </label>
-
   <label>
     <input type="checkbox" id="autoCloseCheckbox">Auto-close
   </label>

chrome/browser/resources/tab_strip/tab_list.js

@@ -130,12 +130,6 @@ class TabListElement extends CustomElement {
     if (loadTimeData.getBoolean('showDemoOptions')) {
       this.shadowRoot.querySelector('#demoOptions').style.display = 'block';
 
-      const mruCheckbox = this.shadowRoot.querySelector('#mruCheckbox');
-      mruCheckbox.checked = tabStripOptions.mruEnabled;
-      mruCheckbox.addEventListener('change', () => {
-        tabStripOptions.mruEnabled = mruCheckbox.checked;
-      });
-
       const autoCloseCheckbox =
           this.shadowRoot.querySelector('#autoCloseCheckbox');
       autoCloseCheckbox.checked = tabStripOptions.autoCloseEnabled;
@@ -170,7 +164,7 @@ class TabListElement extends CustomElement {
 
     this.tabsApi_.getTabs().then(tabs => {
       tabs.forEach(tab => this.onTabCreated_(tab));
-      this.moveOrScrollToActiveTab_();
+      this.scrollToActiveTab_();
 
       addWebUIListener('tab-created', tab => this.onTabCreated_(tab));
       addWebUIListener(
@@ -255,23 +249,6 @@ class TabListElement extends CustomElement {
     }
   }
 
-  /** @private */
-  moveOrScrollToActiveTab_() {
-    const activeTab = this.getActiveTab_();
-    if (!activeTab) {
-      return;
-    }
-
-    if (tabStripOptions.mruEnabled &&
-        !this.tabStripEmbedderProxy_.isVisible() && !activeTab.tab.pinned &&
-        this.tabsContainerElement_.firstChild !== activeTab) {
-      this.tabsApi_.moveTab(
-          activeTab.tab.id, this.pinnedTabsContainerElement_.childElementCount);
-    } else {
-      this.scrollToTab_(activeTab);
-    }
-  }
-
   /**
    * @param {!Event} event
    * @private
@@ -284,7 +261,7 @@ class TabListElement extends CustomElement {
 
   /** @private */
   onDocumentVisibilityChange_() {
-    this.moveOrScrollToActiveTab_();
+    this.scrollToActiveTab_();
     Array.from(this.tabsContainerElement_.children)
         .forEach((tabElement) => this.updateThumbnailTrackStatus_(tabElement));
   }
@@ -338,16 +315,6 @@ class TabListElement extends CustomElement {
       return;
     }
 
-    if (tabStripOptions.mruEnabled && !draggedItem.tab.pinned) {
-      // If MRU is enabled, unpinned tabs should not be draggable.
-      event.preventDefault();
-      return;
-    }
-
-    if (tabStripOptions.mruEnabled) {
-      assert(draggedItem.tab.pinned);
-    }
-
     this.draggedItem_ = /** @type {!TabElement} */ (draggedItem);
     this.draggedItem_.setDragging(true);
     event.dataTransfer.effectAllowed = 'move';
@@ -387,7 +354,7 @@ class TabListElement extends CustomElement {
     if (newlyActiveTab) {
       newlyActiveTab.tab = /** @type {!TabData} */ (
           Object.assign({}, newlyActiveTab.tab, {active: true}));
-      this.moveOrScrollToActiveTab_();
+      this.scrollToActiveTab_();
     }
   }
 
@@ -397,22 +364,9 @@ class TabListElement extends CustomElement {
    */
   onTabCreated_(tab) {
     const tabElement = this.createTabElement_(tab);
-    if (tabStripOptions.mruEnabled && tab.active && !tab.pinned &&
-        tab.index !== this.pinnedTabsContainerElement_.childElementCount) {
-      // Newly created active tabs should first be moved to the very beginning
-      // of the tab strip to enforce the tab strip's most recently used ordering
-      this.tabsApi_
-          .moveTab(tab.id, this.pinnedTabsContainerElement_.childElementCount)
-          .then(() => {
-            this.insertTabOrMoveTo_(
-                tabElement, this.pinnedTabsContainerElement_.childElementCount);
-            this.addAnimationPromise_(tabElement.slideIn());
-          });
-    } else {
     this.insertTabOrMoveTo_(tabElement, tab.index);
     this.addAnimationPromise_(tabElement.slideIn());
   }
-  }
 
   /**
    * @param {number} tabId
@@ -490,6 +444,16 @@ class TabListElement extends CustomElement {
     }
   }
 
+  /** @private */
+  scrollToActiveTab_() {
+    const activeTab = this.getActiveTab_();
+    if (!activeTab) {
+      return;
+    }
+
+    this.scrollToTab_(activeTab);
+  }
+
   /**
    * @param {!TabElement} tabElement
    * @private

chrome/browser/resources/tab_strip/tab_strip_options.js

@@ -9,5 +9,4 @@
  */
 export const tabStripOptions = {
   autoCloseEnabled: true,
-  mruEnabled: true,
 };

chrome/test/data/webui/tab_strip/tab_list_test.js

@@ -218,20 +218,6 @@ suite('TabList', () => {
     assertEquals(tabElements[0].tab, prependedTab);
   });
 
-  test('adds a new tab element to the start when it is active', async () => {
-    const newActiveTab = {
-      alertStates: [],
-      active: true,
-      id: 3,
-      index: 3,
-      title: 'New tab',
-    };
-    webUIListenerCallback('tab-created', newActiveTab);
-    const [tabId, newIndex] = await testTabsApiProxy.whenCalled('moveTab');
-    assertEquals(tabId, newActiveTab.id);
-    assertEquals(newIndex, 0);
-  });
-
   test('removes a tab when tab is removed from current window', async () => {
     const tabToRemove = tabs[0];
     webUIListenerCallback('tab-removed', tabToRemove.id);
@@ -400,22 +386,6 @@ suite('TabList', () => {
     assertEquals(newIndex, dragOverIndex);
   });
 
-  test(
-      'when the tab strip closes, the active tab should move to the start',
-      async () => {
-        // Mock activating the 2nd tab
-        webUIListenerCallback('tab-active-changed', tabs[1].id);
-        testTabsApiProxy.resetResolver('moveTab');
-
-        // Mock tab strip going from visible to hidden
-        testTabStripEmbedderProxy.setVisible(false);
-        document.dispatchEvent(new Event('visibilitychange'));
-
-        const [moveId, newIndex] = await testTabsApiProxy.whenCalled('moveTab');
-        assertEquals(moveId, tabs[1].id);
-        assertEquals(newIndex, 0);
-      });
-
   test('tracks and untracks thumbnails based on viewport', async () => {
     // Wait for slideIn animations to complete updating widths and reset
     // resolvers to track new calls.