customtabs: Create a spare WebContents in warmup() on non low-end devices.

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

 // Copyright 2015 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.customtabs;
 
+import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_NON_LOW_END_DEVICE;
+
 import android.app.Application;
 import android.content.Context;
 import android.net.Uri;
 import android.os.Build;
+import android.os.Bundle;
 import android.os.Process;
 import android.support.customtabs.ICustomTabsCallback;
 import android.test.InstrumentationTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
+import org.chromium.base.ThreadUtils;
+import org.chromium.base.test.util.Restriction;
+import org.chromium.content_public.browser.WebContents;
+
 /** Tests for CustomTabsConnection. */
 public class CustomTabsConnectionTest extends InstrumentationTestCase {
     private CustomTabsConnection mCustomTabsConnection;
     private static final String URL = "http://www.google.com";
     private static final String URL2 = "https://www.android.com";
     private static final String INVALID_SCHEME_URL = "intent://www.google.com";
 
     private Context mContext;
 
     @Override
@@ skipping 35 matching lines @@
     /**
      * Tests that {@link CustomTabsConnection#warmup(long)} succeeds and can
      * be issued multiple times.
      */
     @SmallTest
     public void testCanWarmup() {
         assertEquals(true, mCustomTabsConnection.warmup(0));
         assertEquals(true, mCustomTabsConnection.warmup(0));
     }
 
+    @SmallTest
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    public void testCreateSpareRenderer() {
+        assertTrue(mCustomTabsConnection.warmup(0));
+        // On UI thread because:
+        // 1. takeSpareWebContents needs to be called from the UI thread.
+        // 2. warmup() is non-blocking and posts tasks to the UI thread, it ensures proper ordering.
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                assertNotNull(mCustomTabsConnection.takeSpareWebContents());
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
+            }
+        });
+    }
+
+    @SmallTest
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    public void testCreateSpareRendererCanBeRecreated() {
+        assertTrue(mCustomTabsConnection.warmup(0));
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                assertSpareWebContentsNotNullAndDestroy();
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
+            }
+        });
+        assertTrue(mCustomTabsConnection.warmup(0));
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                assertSpareWebContentsNotNullAndDestroy();
+            }
+        });
+    }
+
+    @SmallTest
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    public void testPrerenderDestroysSpareRenderer() {
+        final ICustomTabsCallback cb = assertWarmupAndMayLaunchUrl(null, URL, true);
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                assertNull(mCustomTabsConnection.takeSpareWebContents());
+                String referrer =
+                        mCustomTabsConnection.getReferrerForSession(cb.asBinder()).getUrl();
+                WebContents webContents =
+                        mCustomTabsConnection.takePrerenderedUrl(cb.asBinder(), URL, referrer);
+                assertNotNull(webContents);
+                webContents.destroy();
+            }
+        });
+    }
+
+    @SmallTest
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    public void testMayLaunchUrlKeepsSpareRendererWithoutPrerendering() {
+        assertTrue(mCustomTabsConnection.warmup(0));
+        final ICustomTabsCallback cb = new CustomTabsTestUtils.DummyCallback();
+        assertTrue(mCustomTabsConnection.newSession(cb));
+
+        Bundle extras = new Bundle();
+        extras.putBoolean(CustomTabsConnection.NO_PRERENDERING_KEY, true);
+        assertTrue(mCustomTabsConnection.mayLaunchUrl(cb, Uri.parse(URL), extras, null));
+
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                assertSpareWebContentsNotNullAndDestroy();
+            }
+        });
+    }
+
+    private void assertSpareWebContentsNotNullAndDestroy() {

[pasko, 2015/10/29 13:38:58]

nit: s/Destroy/CanBeDestroyed/

[Benoit L, 2015/10/29 17:12:36]

There is no assertion here that we can destroy the WebContents, it is just
destroying it to avoid having too many renderers laying around (which could make
tests fail).

+        WebContents webContents = mCustomTabsConnection.takeSpareWebContents();
+        assertNotNull(webContents);
+        webContents.destroy();
+    }
+
     /**
      * Calls warmup() and mayLaunchUrl(), checks for the expected result
      * (success or failure) and returns the result code.
      */
     private ICustomTabsCallback assertWarmupAndMayLaunchUrl(
             ICustomTabsCallback cb, String url, boolean shouldSucceed) {
         mCustomTabsConnection.warmup(0);
         if (cb == null) {
             cb = new CustomTabsTestUtils.DummyCallback();
             mCustomTabsConnection.newSession(cb);
@@ skipping 145 matching lines @@
         ICustomTabsCallback cb = assertWarmupAndMayLaunchUrl(null, URL, true);
         mCustomTabsConnection.resetThrottling(mContext, Process.myUid());
         ICustomTabsCallback cb2 = assertWarmupAndMayLaunchUrl(null, URL, true);
         mCustomTabsConnection.resetThrottling(mContext, Process.myUid());
         for (int i = 0; i < 10; i++) {
             mCustomTabsConnection.mayLaunchUrl(cb, Uri.parse(URL), null, null);
         }
         assertWarmupAndMayLaunchUrl(cb2, URL, false);
     }
 }