[Feed] Add unit tests for StreamLifecycleManager

Bug: 851977
Change-Id: I99de0abe80ea536a23ecdca2401dd3fd6b816955
Reviewed-on: https://chromium-review.googlesource.com/1101699
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568481}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/StreamLifecycleManager.java

@@ -11,6 +11,7 @@ import com.google.android.libraries.feed.api.stream.Stream;
 
 import org.chromium.base.ActivityState;
 import org.chromium.base.ApplicationStatus;
+import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TabObserver;
@@ -160,7 +161,7 @@ class StreamLifecycleManager implements ApplicationStatus.ActivityStateListener
 
     /** Calls {@link Stream#onHide()}. */
     private void hide() {
-        if (mStreamState == HIDDEN || mStreamState == DESTROYED) return;
+        if (mStreamState == HIDDEN || mStreamState == CREATED || mStreamState == DESTROYED) return;
 
         deactivate();
         mStreamState = HIDDEN;
@@ -180,4 +181,9 @@ class StreamLifecycleManager implements ApplicationStatus.ActivityStateListener
         ApplicationStatus.unregisterActivityStateListener(this);
         mStream.onDestroy();
     }
+
+    @VisibleForTesting
+    TabObserver getTabObserverForTesting() {
+        return mTabObserver;
+    }
 }

chrome/android/java_sources.gni

@@ -2201,8 +2201,10 @@ if (enable_offline_pages_harness) {
 }
 
 if (enable_feed_in_chrome) {
-  chrome_junit_test_java_sources +=
-      [ "junit/src/org/chromium/chrome/browser/feed/FeedImageLoaderTest.java" ]
+  chrome_junit_test_java_sources += [
+    "junit/src/org/chromium/chrome/browser/feed/FeedImageLoaderTest.java",
+    "junit/src/org/chromium/chrome/browser/feed/StreamLifecycleManagerTest.java",
+  ]
   chrome_test_java_sources += feed_conformance_test_sources
 }
 

chrome/android/junit/src/org/chromium/chrome/browser/feed/OWNERS

+# For tests that apply to parts of feature implemented in components with a thin Java layer (e.g. host APIs).
 file://components/feed/OWNERS
 
+# For tests affecting Android specific parts (e.g. Stream).
+file://chrome/android/feed/OWNERS