[OfflinePages] Do not start background loading on low-end devices if app has any visible Activities.

chrome/android/junit/src/org/chromium/chrome/browser/offlinepages/BackgroundOfflinerTaskTest.java

Index: chrome/android/junit/src/org/chromium/chrome/browser/offlinepages/BackgroundOfflinerTaskTest.java
diff --git a/chrome/android/junit/src/org/chromium/chrome/browser/offlinepages/BackgroundOfflinerTaskTest.java b/chrome/android/junit/src/org/chromium/chrome/browser/offlinepages/BackgroundOfflinerTaskTest.java
index e4d58c9bcd3321ec0209bdc81202f0171917463f..ec39b81db381b59da37de6fe793f13f1d103f43d 100644
--- a/chrome/android/junit/src/org/chromium/chrome/browser/offlinepages/BackgroundOfflinerTaskTest.java
+++ b/chrome/android/junit/src/org/chromium/chrome/browser/offlinepages/BackgroundOfflinerTaskTest.java
@@ -13,17 +13,24 @@ import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.when;
 
+import android.app.Activity;
 import android.content.Context;
 import android.os.Bundle;
 
 import com.google.android.gms.gcm.Task;
 
+import org.chromium.base.ActivityState;
+import org.chromium.base.ApplicationStatus;
 import org.chromium.base.BaseChromiumApplication;
+import org.chromium.base.BaseSwitches;
+import org.chromium.base.CommandLine;
+import org.chromium.base.SysUtils;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.browser.ChromeBackgroundServiceWaiter;
 import org.chromium.net.ConnectionType;
 import org.chromium.testing.local.LocalRobolectricTestRunner;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -44,6 +51,8 @@ public class BackgroundOfflinerTaskTest {
     private static final boolean REQUIRE_UNMETERED = true;
     private static final boolean POWER_CONNECTED = true;
     private static final int MINIMUM_BATTERY_LEVEL = 33;
+    private static final String IS_LOW_END_DEVICE_SWITCH =
+            "--" + BaseSwitches.ENABLE_LOW_END_DEVICE_MODE;
 
     @Mock
     private OfflinePageUtils mOfflinePageUtils;
@@ -55,6 +64,7 @@ public class BackgroundOfflinerTaskTest {
             new TriggerConditions(!REQUIRE_POWER, MINIMUM_BATTERY_LEVEL, REQUIRE_UNMETERED);
     private DeviceConditions mDeviceConditions = new DeviceConditions(
             !POWER_CONNECTED, MINIMUM_BATTERY_LEVEL + 5, ConnectionType.CONNECTION_3G);
+    private Activity mTestActivity;
 
     @Before
     public void setUp() throws Exception {
@@ -71,6 +81,23 @@ public class BackgroundOfflinerTaskTest {
         mStubBackgroundSchedulerProcessor = new StubBackgroundSchedulerProcessor();
         RecordHistogram.disableForTests();
         ShadowGcmNetworkManager.clear();
+
+        // Run tests as a low-end device.
+        CommandLine.init(new String[] {"testcommand", IS_LOW_END_DEVICE_SWITCH});

[pasko, 2016/07/29 09:58:17]

did you not choose
@CommandLineFlags.Add(BaseSwitches.ENABLE_LOW_END_DEVICE_MODE) because you
explicitly wanted to run all tests as low end device?

[dougarnett, 2016/07/29 15:55:26]

This was a bit interesting. I did try that annotation initially without getting
the desired effect.

I did get it to work with init() but later learned there is an issue with
SysUtils caching the value it first calculates - so whichever test runs first
set the flag and subsequent tests don't actually look at the command switch,
just use the cached value. I added a SysUtils.reset() method and now call it it
tearDown to isolate the command switch interpretation. 

Since figuring that out I have not gone back to try the annotation instead of
init(). I should do that and see if it looks better.

+
+        // Set up single, stopped Activity.
+        ApplicationStatus.destroyForJUnitTests();
+        mTestActivity = new Activity();
+        ApplicationStatus.onStateChangeForTesting(mTestActivity, ActivityState.CREATED);
+        ApplicationStatus.onStateChangeForTesting(mTestActivity, ActivityState.STOPPED);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        // Clean up static state for subsequent Robolectric tests.
+        CommandLine.reset();
+        SysUtils.reset();
+        ApplicationStatus.destroyForJUnitTests();
     }
 
     @Test
@@ -138,4 +165,33 @@ public class BackgroundOfflinerTaskTest {
         ChromeBackgroundServiceWaiter waiter2 = new ChromeBackgroundServiceWaiter(1);
         assertTrue(task2.startBackgroundRequests(Robolectric.application, mTaskExtras, waiter2));
     }
+
+    @Test
+    @Feature({"OfflinePages"})
+    public void testStartBackgroundRequestsForRunningActivityOnLowEndDevice() {
+        BackgroundOfflinerTask task = new BackgroundOfflinerTask(mStubBackgroundSchedulerProcessor);
+        ChromeBackgroundServiceWaiter waiter = new ChromeBackgroundServiceWaiter(1);
+        assertNull("Nothing scheduled", ShadowGcmNetworkManager.getScheduledTask());
+
+        // Transition the test Activity to a running state.
+        ApplicationStatus.onStateChangeForTesting(mTestActivity, ActivityState.STARTED);
+
+        assertFalse(task.startBackgroundRequests(Robolectric.application, mTaskExtras, waiter));
+
+        // Check that the backup task was scheduled.
+        Task gcmTask = ShadowGcmNetworkManager.getScheduledTask();
+        assertNotNull("Backup task scheduled", gcmTask);
+        assertEquals(mTriggerConditions,
+                TaskExtrasPacker.unpackTriggerConditionsFromBundle(gcmTask.getExtras()));
+
+        // Check that startProcessing was NOT called.
+        assertFalse(mStubBackgroundSchedulerProcessor.getStartProcessingCalled());
+
+        // Now verify will start processing when Activity is stopped.
+        ApplicationStatus.onStateChangeForTesting(mTestActivity, ActivityState.STOPPED);
+        BackgroundOfflinerTask task2 =
+                new BackgroundOfflinerTask(mStubBackgroundSchedulerProcessor);
+        ChromeBackgroundServiceWaiter waiter2 = new ChromeBackgroundServiceWaiter(1);
+        assertTrue(task2.startBackgroundRequests(Robolectric.application, mTaskExtras, waiter2));
+    }
 }