Convert and add several tests by Espresso API and a custom test rule for DownloadActivity.

Add a custom ActivityTestRule for DownloadActivity which can turn off animation scales during tests.

Spinner is removed in Download Home V2

Bug: 904030
Change-Id: If00ea1400b17bdbbc49fe2414d0c80a5ec47885b
Reviewed-on: https://chromium-review.googlesource.com/c/1278207
Commit-Queue: Yun Liu <yliuyliu@google.com>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612390}

chrome/android/java_sources.gni

@@ -1935,6 +1935,7 @@ chrome_test_java_sources = [
   "javatests/src/org/chromium/chrome/browser/dom_distiller/DistillabilityServiceTest.java",
   "javatests/src/org/chromium/chrome/browser/dom_distiller/DistilledPagePrefsTest.java",
   "javatests/src/org/chromium/chrome/browser/download/ChromeDownloadDelegateTest.java",
+  "javatests/src/org/chromium/chrome/browser/download/DisableAnimationsRule.java",
   "javatests/src/org/chromium/chrome/browser/download/DownloadActivityTest.java",
   "javatests/src/org/chromium/chrome/browser/download/DownloadInfoBarControllerTest.java",
   "javatests/src/org/chromium/chrome/browser/download/DownloadManagerServiceTest.java",

chrome/android/javatests/AndroidManifest.xml

@@ -9,6 +9,7 @@
 {% block extra_uses_permissions %}
     <uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
     <uses-permission android:name="android.permission.READ_LOGS"/>
+    <uses-permission android:name="android.permission.SET_ANIMATION_SCALE"/>
 {% endblock %}
 
 {% block extra_application_definitions_for_test %}

chrome/android/javatests/src/org/chromium/chrome/browser/download/DisableAnimationsRule.java

+// Copyright 2018 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.download;
+
+import android.os.IBinder;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import org.chromium.base.Log;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+
+/**
+ * {@link TestRule} to disable animations for UI testing.
+ */
+public class DisableAnimationsRule implements TestRule {
+    private Method mSetAnimationScalesMethod;
+    private Method mGetAnimationScalesMethod;
+    private Object mWindowManagerObject;
+
+    private static final float DISABLED_SCALE_FACTOR = 0.0f;
+    private static final float DEFAULT_SCALE_FACTOR = 1.0f;
+    private static final String TAG = "disable_animations";
+
+    /**
+     * Invoke setAnimationScalesMethod to turn off system animations, such as Window animation
+     * scale, Transition animation scale, Animator duration scale, which can improve stability
+     * and reduce flakiness for UI testing.
+     */
+    public DisableAnimationsRule() {
+        try {
+            Class<?> windowManagerStubClazz = Class.forName("android.view.IWindowManager$Stub");
+            Method asInterface =
+                    windowManagerStubClazz.getDeclaredMethod("asInterface", IBinder.class);
+            Class<?> serviceManagerClazz = Class.forName("android.os.ServiceManager");
+            Method getService = serviceManagerClazz.getDeclaredMethod("getService", String.class);
+            Class<?> windowManagerClazz = Class.forName("android.view.IWindowManager");
+            mSetAnimationScalesMethod =
+                    windowManagerClazz.getDeclaredMethod("setAnimationScales", float[].class);
+            mGetAnimationScalesMethod = windowManagerClazz.getDeclaredMethod("getAnimationScales");
+            IBinder windowManagerBinder = (IBinder) getService.invoke(null, "window");
+            mWindowManagerObject = asInterface.invoke(null, windowManagerBinder);
+        } catch (Exception e) {
+            Log.w(TAG, "Failed to access animation methods", e);
+        }
+    }
+
+    @Override
+    public Statement apply(final Statement statement, Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                setAnimationScaleFactors(DISABLED_SCALE_FACTOR);
+                try {
+                    statement.evaluate();
+                } finally {
+                    setAnimationScaleFactors(DEFAULT_SCALE_FACTOR);
+                }
+            }
+        };
+    }
+
+    private void setAnimationScaleFactors(float scaleFactor) {
+        try {
+            float[] scaleFactors = (float[]) mGetAnimationScalesMethod.invoke(mWindowManagerObject);
+            Arrays.fill(scaleFactors, scaleFactor);
+            mSetAnimationScalesMethod.invoke(mWindowManagerObject, scaleFactors);
+        } catch (Exception e) {
+            Log.w(TAG, "Failed to set animation scale factors", e);
+        }
+    }
+}