Revert of Android: Make the spare renderer accessible to all Chrome tabs....

Revert of Android: Make the spare renderer accessible to all Chrome tabs. (patchset #7 id:120001 of https://codereview.chromium.org/2199393002/ )

Reason for revert:
New test WarmupManagerTest#testCreateAndTakeSpareRenderer failing on 3 different bots:
https://build.chromium.org/p/chromium.linux/builders/Android%20Tests%20%28dbg%29/builds/35784
https://build.chromium.org/p/chromium.android/builders/KitKat%20Tablet%20Tester/builds/5165
https://build.chromium.org/p/chromium.android/builders/Jelly%20Bean%20Tester/builds/5527

Original issue's description:
> Android: Make the spare renderer accessible to all Chrome tabs.
>
> In Custom Tabs, an external application can "warm up" Chrome. This
> creates and initializes a spare renderer, and has been found to be a
> significant optimization for loading performance.
>
> This patch moves the spare renderer logic out of Custom Tabs, and makes
> it accessible and useful for regular navigations in Chrome. Note that
> this patch doesn't add new call sites for the spare renderer creation.
>
> BUG=633964
>
> Committed: https://crrev.com/f7ce563033df1df90b314e4f727596c93c2b3d6d
> Cr-Commit-Position: refs/heads/master@{#412510}

TBR=yusufo@chromium.org,mariakhomenko@chromium.org,lizeb@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=633964

Review-Url: https://codereview.chromium.org/2254863002
Cr-Commit-Position: refs/heads/master@{#412565}

chrome/android/java/src/org/chromium/chrome/browser/WarmupManager.java

@@ -15,13 +15,11 @@ import android.view.ViewStub;
 import android.widget.FrameLayout;
 
 import org.chromium.base.Log;
-import org.chromium.base.SysUtils;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.TraceEvent;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.net.spdyproxy.DataReductionProxySettings;
 import org.chromium.chrome.browser.profiles.Profile;
-import org.chromium.content_public.browser.WebContents;
 
 import java.net.InetAddress;
 import java.net.MalformedURLException;
@@ -48,7 +46,6 @@ public final class WarmupManager {
 
     private int mToolbarContainerId;
     private ViewGroup mMainView;
-    private WebContents mSpareWebContents;
 
     /**
      * @return The singleton instance for the WarmupManager, creating one if necessary.
@@ -195,50 +192,5 @@ public final class WarmupManager {
         }
     }
 
-    /**
-     * Creates and initializes a spare WebContents, to be used in a subsequent navigation.
-     *
-     * This creates a renderer that is suitable for any navigation. It can be picked up by any tab.
-     * Can be called multiple times, and must be called from the UI thread.
-     * Note that this is a no-op on low-end devices.
-     */
-    public void createSpareWebContents() {
-        ThreadUtils.assertOnUiThread();
-        if (mSpareWebContents != null || SysUtils.isLowEndDevice()) return;
-        mSpareWebContents = WebContentsFactory.createWebContentsWithWarmRenderer(false, false);
-    }
-
-    /**
-     * Destroys the spare WebContents if there is one.
-     */
-    public void destroySpareWebContents() {
-        ThreadUtils.assertOnUiThread();
-        if (mSpareWebContents == null) return;
-        mSpareWebContents.destroy();
-        mSpareWebContents = null;
-    }
-
-    /**
-     * Returns a spare WebContents or null, depending on the availability of one.
-     *
-     * The parameters are the same as for {@link WebContentsFactory#createWebContents()}.
-     *
-     * @return a WebContents, or null.
-     */
-    public WebContents takeSpareWebContents(boolean incognito, boolean initiallyHidden) {
-        ThreadUtils.assertOnUiThread();
-        if (incognito || initiallyHidden) return null;
-        WebContents result = mSpareWebContents;
-        mSpareWebContents = null;
-        return result;
-    }
-
-    /**
-     * @return Whether a spare renderer is available.
-     */
-    public boolean hasSpareWebContents() {
-        return mSpareWebContents != null;
-    }
-
     private static native void nativePreconnectUrlAndSubresources(Profile profile, String url);
 }

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java

@@ -40,7 +40,6 @@ import org.chromium.chrome.browser.ChromeTabbedActivity;
 import org.chromium.chrome.browser.IntentHandler;
 import org.chromium.chrome.browser.IntentHandler.ExternalAppId;
 import org.chromium.chrome.browser.KeyboardShortcuts;
-import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.WebContentsFactory;
 import org.chromium.chrome.browser.appmenu.AppMenuPropertiesDelegate;
 import org.chromium.chrome.browser.compositor.layouts.LayoutManagerDocument;
@@ -96,12 +95,10 @@ public class CustomTabActivity extends ChromeActivity {
 
     private boolean mHasCreatedTabEarly;
     private boolean mIsInitialStart = true;
-    // Whether there is any prerender associated with the session.
     private boolean mHasPrerender;
     private CustomTabObserver mTabObserver;
 
     private String mPrerenderedUrl;
-    // Whether a prerender is being used.
     private boolean mHasPrerendered;
 
     private static class PageLoadMetricsObserver implements PageLoadMetrics.Observer {
@@ -255,8 +252,7 @@ public class CustomTabActivity extends ChromeActivity {
 
     @Override
     public boolean shouldAllocateChildConnection() {
-        return !mHasCreatedTabEarly && !mHasPrerender
-                && !WarmupManager.getInstance().hasSpareWebContents();
+        return !mHasCreatedTabEarly && !mHasPrerender;
     }
 
     @Override
@@ -423,9 +419,7 @@ public class CustomTabActivity extends ChromeActivity {
         WebContents webContents =
                 customTabsConnection.takePrerenderedUrl(mSession, url, referrerUrl);
         mHasPrerendered = webContents != null;
-        if (!mHasPrerendered) {
-            webContents = WarmupManager.getInstance().takeSpareWebContents(false, false);
-        }
+        if (webContents == null) webContents = customTabsConnection.takeSpareWebContents();
         if (webContents == null) webContents = WebContentsFactory.createWebContents(false, false);
         tab.initialize(webContents, getTabContentManager(),
                 new CustomTabDelegateFactory(mIntentDataProvider.shouldEnableUrlBarHiding()), false,

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java

@@ -38,6 +38,7 @@ import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeApplication;
 import org.chromium.chrome.browser.IntentHandler;
 import org.chromium.chrome.browser.WarmupManager;
+import org.chromium.chrome.browser.WebContentsFactory;
 import org.chromium.chrome.browser.device.DeviceClassManager;
 import org.chromium.chrome.browser.init.ChromeBrowserInitializer;
 import org.chromium.chrome.browser.net.spdyproxy.DataReductionProxySettings;
@@ -105,6 +106,7 @@ public class CustomTabsConnection {
     private final AtomicBoolean mWarmupHasBeenCalled = new AtomicBoolean();
     private final AtomicBoolean mWarmupHasBeenFinished = new AtomicBoolean();
     private ExternalPrerenderHandler mExternalPrerenderHandler;
+    private WebContents mSpareWebContents;
     // TODO(lizeb): Remove once crbug.com/630303 is fixed.
     private boolean mPageLoadMetricsEnabled;
 
@@ -220,7 +222,7 @@ public class CustomTabsConnection {
             public void run() {
                 if (!initialized) initializeBrowser(mApplication);
                 if (mayCreateSpareWebContents && mPrerender == null && !SysUtils.isLowEndDevice()) {
-                    WarmupManager.getInstance().createSpareWebContents();
+                    createSpareWebContents();
                 }
                 mWarmupHasBeenFinished.set(true);
             }
@@ -228,6 +230,13 @@ public class CustomTabsConnection {
         return true;
     }
 
+    /** Creates a spare {@link WebContents}, if none exists. */
+    private void createSpareWebContents() {
+        ThreadUtils.assertOnUiThread();
+        if (mSpareWebContents != null) return;
+        mSpareWebContents = WebContentsFactory.createWebContentsWithWarmRenderer(false, false);
+    }
+
     /** @return the URL converted to string, or null if it's invalid. */
     private static String checkAndConvertUri(Uri uri) {
         if (uri == null) return null;
@@ -262,7 +271,7 @@ public class CustomTabsConnection {
             didStartPrerender = prerenderUrl(session, url, extras, uid);
         }
         preconnectUrls(otherLikelyBundles);
-        if (!didStartPrerender) WarmupManager.getInstance().createSpareWebContents();
+        if (!didStartPrerender) createSpareWebContents();
     }
 
     /**
@@ -274,7 +283,7 @@ public class CustomTabsConnection {
     boolean lowConfidenceMayLaunchUrl(List<Bundle> likelyBundles) {
         ThreadUtils.assertOnUiThread();
         if (!preconnectUrls(likelyBundles)) return false;
-        WarmupManager.getInstance().createSpareWebContents();
+        createSpareWebContents();
         return true;
     }
 
@@ -343,6 +352,20 @@ public class CustomTabsConnection {
         return null;
     }
 
+    /** @return a spare WebContents, or null. */
+    WebContents takeSpareWebContents() {
+        ThreadUtils.assertOnUiThread();
+        WebContents result = mSpareWebContents;
+        mSpareWebContents = null;
+        return result;
+    }
+
+    private void destroySpareWebContents() {
+        ThreadUtils.assertOnUiThread();
+        WebContents webContents = takeSpareWebContents();
+        if (webContents != null) webContents.destroy();
+    }
+
     public boolean updateVisuals(final CustomTabsSessionToken session, Bundle bundle) {
         final Bundle actionButtonBundle = IntentUtils.safeGetBundle(bundle,
                 CustomTabsIntent.EXTRA_ACTION_BUTTON_BUNDLE);
@@ -735,7 +758,7 @@ public class CustomTabsConnection {
         if (throttle && !mClientManager.isPrerenderingAllowed(uid)) return false;
 
         // A prerender will be requested. Time to destroy the spare WebContents.
-        WarmupManager.getInstance().destroySpareWebContents();
+        destroySpareWebContents();
 
         Intent extrasIntent = new Intent();
         if (extras != null) extrasIntent.putExtras(extras);
@@ -763,6 +786,8 @@ public class CustomTabsConnection {
         return true;
     }
 
+
+
     @VisibleForTesting
     void resetThrottling(Context context, int uid) {
         mClientManager.resetThrottling(uid);

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

@@ -52,7 +52,6 @@ import org.chromium.chrome.browser.SwipeRefreshHandler;
 import org.chromium.chrome.browser.TabState;
 import org.chromium.chrome.browser.TabState.WebContentsState;
 import org.chromium.chrome.browser.UrlConstants;
-import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.WebContentsFactory;
 import org.chromium.chrome.browser.banners.AppBannerManager;
 import org.chromium.chrome.browser.compositor.layouts.content.TabContentManager;
@@ -1462,12 +1461,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
 
             boolean creatingWebContents = webContents == null;
             if (creatingWebContents) {
-                webContents = WarmupManager.getInstance().takeSpareWebContents(
-                        isIncognito(), initiallyHidden);
-                if (webContents == null) {
-                    webContents =
-                            WebContentsFactory.createWebContents(isIncognito(), initiallyHidden);
-                }
+                webContents = WebContentsFactory.createWebContents(isIncognito(), initiallyHidden);
             }
 
             ContentViewCore contentViewCore = ContentViewCore.fromWebContents(webContents);

chrome/android/java_sources.gni

@@ -1095,7 +1095,6 @@ chrome_test_java_sources = [
   "javatests/src/org/chromium/chrome/browser/TabsTest.java",
   "javatests/src/org/chromium/chrome/browser/UrlSchemeTest.java",
   "javatests/src/org/chromium/chrome/browser/UsbChooserDialogTest.java",
-  "javatests/src/org/chromium/chrome/browser/WarmupManagerTest.java",
   "javatests/src/org/chromium/chrome/browser/accessibility/FontSizePrefsTest.java",
   "javatests/src/org/chromium/chrome/browser/appmenu/AppMenuTest.java",
   "javatests/src/org/chromium/chrome/browser/autofill/AutofillKeyboardAccessoryTest.java",

chrome/android/javatests/src/org/chromium/chrome/browser/WarmupManagerTest.java

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.chrome.browser;
-
-import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_LOW_END_DEVICE;
-import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_NON_LOW_END_DEVICE;
-
-import android.test.UiThreadTest;
-import android.test.suitebuilder.annotation.SmallTest;
-
-import org.chromium.base.ThreadUtils;
-import org.chromium.base.test.util.Restriction;
-import org.chromium.content.browser.test.NativeLibraryTestBase;
-import org.chromium.content.browser.test.util.Criteria;
-import org.chromium.content.browser.test.util.CriteriaHelper;
-import org.chromium.content_public.browser.WebContents;
-import org.chromium.content_public.browser.WebContentsObserver;
-
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicReference;
-
-/** Tests for {@link WarmupManager} */
-public class WarmupManagerTest extends NativeLibraryTestBase {
-    private WarmupManager mWarmupManager;
-
-    @Override
-    protected void setUp() throws Exception {
-        super.setUp();
-        loadNativeLibraryAndInitBrowserProcess();
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                mWarmupManager = WarmupManager.getInstance();
-            }
-        });
-    }
-
-    @Override
-    protected void tearDown() throws Exception {
-        super.tearDown();
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                mWarmupManager.destroySpareWebContents();
-            }
-        });
-    }
-
-    @SmallTest
-    @Restriction(RESTRICTION_TYPE_LOW_END_DEVICE)
-    @UiThreadTest
-    public void testNoSpareRendererOnLowEndDevices() {
-        mWarmupManager.createSpareWebContents();
-        assertFalse(mWarmupManager.hasSpareWebContents());
-    }
-
-    @SmallTest
-    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
-    public void testCreateAndTakeSpareRenderer() throws Exception {
-        final AtomicBoolean isRenderViewReady = new AtomicBoolean();
-        final AtomicReference<WebContents> webContentsReference = new AtomicReference<>();
-        final WebContentsObserver observer = new WebContentsObserver() {
-            @Override
-            public void renderViewReady() {
-                isRenderViewReady.set(true);
-            }
-        };
-
-        ThreadUtils.runOnUiThread(new Runnable() {
-            @Override
-            public void run() {
-                mWarmupManager.createSpareWebContents();
-                assertTrue(mWarmupManager.hasSpareWebContents());
-                WebContents webContents = mWarmupManager.takeSpareWebContents(false, false);
-                assertNotNull(webContents);
-                assertFalse(mWarmupManager.hasSpareWebContents());
-                // This is not racy because {@link WebContentsObserver} methods are called on the UI
-                // thread by posting a task. See {@link RenderViewHostImpl::PostRenderViewReady}.
-                webContents.addObserver(observer);
-                webContentsReference.set(webContents);
-            }
-        });
-        CriteriaHelper.pollUiThread(new Criteria("Spare renderer is not initialized") {
-            @Override
-            public boolean isSatisfied() {
-                return isRenderViewReady.get();
-            }
-        });
-        ThreadUtils.runOnUiThread(new Runnable() {
-            @Override
-            public void run() {
-                webContentsReference.get().destroy();
-            }
-        });
-    }
-
-    /** Tests that taking a spare WebContents makes it unavailable to subsequent callers. */
-    @SmallTest
-    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
-    @UiThreadTest
-    public void testTakeSpareWebContents() throws Exception {
-        mWarmupManager.createSpareWebContents();
-        WebContents webContents = mWarmupManager.takeSpareWebContents(false, false);
-        assertNotNull(webContents);
-        assertFalse(mWarmupManager.hasSpareWebContents());
-        webContents.destroy();
-    }
-
-    @SmallTest
-    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
-    @UiThreadTest
-    public void testTakeSpareWebContentsChecksArguments() throws Exception {
-        mWarmupManager.createSpareWebContents();
-        assertNull(mWarmupManager.takeSpareWebContents(true, false));
-        assertNull(mWarmupManager.takeSpareWebContents(false, true));
-        assertNull(mWarmupManager.takeSpareWebContents(true, true));
-        assertTrue(mWarmupManager.hasSpareWebContents());
-    }
-}

chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabActivityTest.java

@@ -1061,13 +1061,9 @@ public class CustomTabActivityTest extends CustomTabActivityTestBase {
         } catch (InterruptedException e) {
             fail();
         }
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                assertFalse("Warmup() should have allocated a child connection",
-                        mActivity.shouldAllocateChildConnection());
-            }
-        });
+        assertFalse(
+                "Warmup() should have allocated a child connection",
+                mActivity.shouldAllocateChildConnection());
     }
 
     /**
@@ -1088,13 +1084,9 @@ public class CustomTabActivityTest extends CustomTabActivityTestBase {
         } catch (InterruptedException e) {
             fail();
         }
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                assertTrue("No spare renderer available, should allocate a child connection.",
-                        mActivity.shouldAllocateChildConnection());
-            }
-        });
+        assertTrue(
+                "No spare renderer available, should allocate a child connection.",
+                mActivity.shouldAllocateChildConnection());
     }
 
     /**
@@ -1114,13 +1106,9 @@ public class CustomTabActivityTest extends CustomTabActivityTestBase {
         } catch (InterruptedException e) {
             fail();
         }
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                assertFalse("Prerendering should have allocated a child connection",
-                        mActivity.shouldAllocateChildConnection());
-            }
-        });
+        assertFalse(
+                "Prerendering should have allocated a child connection",
+                mActivity.shouldAllocateChildConnection());
     }
 
     /**

chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java

@@ -23,7 +23,6 @@ import org.chromium.base.ThreadUtils;
 import org.chromium.base.library_loader.LibraryLoader;
 import org.chromium.base.library_loader.LibraryProcessType;
 import org.chromium.base.test.util.Restriction;
-import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.preferences.PrefServiceBridge;
 import org.chromium.content_public.browser.WebContents;
 
@@ -58,12 +57,6 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
     protected void tearDown() throws Exception {
         super.tearDown();
         CustomTabsTestUtils.cleanupSessions(mCustomTabsConnection);
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                WarmupManager.getInstance().destroySpareWebContents();
-            }
-        });
     }
 
     /**
@@ -109,12 +102,8 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
             public void run() {
-                WarmupManager warmupManager = WarmupManager.getInstance();
-                assertTrue(warmupManager.hasSpareWebContents());
-                WebContents webContents = warmupManager.takeSpareWebContents(false, false);
-                assertNotNull(webContents);
-                assertFalse(warmupManager.hasSpareWebContents());
-                webContents.destroy();
+                assertNotNull(mCustomTabsConnection.takeSpareWebContents());
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
             }
         });
     }
@@ -127,7 +116,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
             @Override
             public void run() {
                 assertSpareWebContentsNotNullAndDestroy();
-                assertFalse(WarmupManager.getInstance().hasSpareWebContents());
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
             }
         });
         assertTrue(mCustomTabsConnection.warmup(0));
@@ -146,7 +135,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
             public void run() {
-                assertFalse(WarmupManager.getInstance().hasSpareWebContents());
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
                 String referrer =
                         mCustomTabsConnection.getReferrerForSession(token).getUrl();
                 WebContents webContents =
@@ -295,7 +284,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
             public void run() {
-                assertNull(WarmupManager.getInstance().takeSpareWebContents(false, false));
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
                 String referrer = mCustomTabsConnection.getReferrerForSession(token).getUrl();
                 assertNotNull(mCustomTabsConnection.takePrerenderedUrl(token, URL, referrer));
             }
@@ -309,7 +298,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
             public void run() {
-                assertNull(WarmupManager.getInstance().takeSpareWebContents(false, false));
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
             }
         });
         assertTrue(mCustomTabsConnection.mayLaunchUrl(token, null, null, null));
@@ -324,7 +313,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
     }
 
     private void assertSpareWebContentsNotNullAndDestroy() {
-        WebContents webContents = WarmupManager.getInstance().takeSpareWebContents(false, false);
+        WebContents webContents = mCustomTabsConnection.takeSpareWebContents();
         assertNotNull(webContents);
         webContents.destroy();
     }
@@ -528,7 +517,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
             public void run() {
-                assertNull(WarmupManager.getInstance().takeSpareWebContents(false, false));
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
                 String referrer = mCustomTabsConnection.getReferrerForSession(token).getUrl();
                 WebContents prerender = mCustomTabsConnection.takePrerenderedUrl(
                         token, URL, referrer);

chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ChromeTabCreatorTest.java

@@ -8,13 +8,11 @@ import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_LOW_END_D
 import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_NON_LOW_END_DEVICE;
 
 import android.os.Environment;
-import android.test.UiThreadTest;
 import android.test.suitebuilder.annotation.MediumTest;
 
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.Restriction;
-import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabLaunchType;
 import org.chromium.chrome.test.ChromeTabbedActivityTestBase;
@@ -105,26 +103,6 @@ public class ChromeTabCreatorTest extends ChromeTabbedActivityTestBase  {
         ChromeTabUtils.waitForTabPageLoaded(bgTab, mTestServer.getURL(TEST_PATH));
     }
 
-    /**
-     * Verify that the spare WebContents is used.
-     *
-     * Spare WebContents are not created on low-devices, so don't run the test.
-     */
-    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
-    @MediumTest
-    @Feature({"Browser"})
-    @UiThreadTest
-    public void testCreateNewTabTakesSpareWebContents()
-            throws ExecutionException, InterruptedException {
-        Tab currentTab = getActivity().getActivityTab();
-        WarmupManager.getInstance().createSpareWebContents();
-        assertTrue(WarmupManager.getInstance().hasSpareWebContents());
-        getActivity().getCurrentTabCreator().createNewTab(
-                new LoadUrlParams(mTestServer.getURL(TEST_PATH)), TabLaunchType.FROM_EXTERNAL_APP,
-                currentTab);
-        assertFalse(WarmupManager.getInstance().hasSpareWebContents());
-    }
-
     /**
      * @return the index of the given tab in the current tab model
      */