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

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

Index: chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ChromeTabCreatorTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ChromeTabCreatorTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ChromeTabCreatorTest.java
index 44052aeaa47901dd0bb3ff3c0839ecb552989b8a..9b25e40834b17ed3710e9d7b81f1227c7650c057 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ChromeTabCreatorTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/ChromeTabCreatorTest.java
@@ -8,11 +8,13 @@ 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;
@@ -104,6 +106,26 @@ public class ChromeTabCreatorTest extends ChromeTabbedActivityTestBase  {
     }
 
     /**
+     * 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
      */
     private int indexOf(Tab tab) {