Add tests for DocumentModeAssassin#isOptedOutOfDocumentMode()

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

Index: chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/DocumentModeAssassinTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/DocumentModeAssassinTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/DocumentModeAssassinTest.java
index 028e84c11f859966ee11c1641c1e52d1c38743f6..7a6c6a8d2972d1a646ce073f8781778d6632f9da 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/DocumentModeAssassinTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/tabmodel/DocumentModeAssassinTest.java
@@ -612,6 +612,45 @@ public class DocumentModeAssassinTest extends NativeLibraryTestBase {
         assertFalse(prefs.contains(keyToBeDeleted));
     }
 
+    @SmallTest
+    public void testIsOptedOutOfDocumentModeMigration() throws Exception {
+        TabPersistentStore.setBaseStateDirectoryForTests(mTabbedModeDirectory.getBaseDirectory());
+        SharedPreferences.Editor sharedPreferencesEditor =
+                ContextUtils.getAppSharedPreferences().edit();
+
+        // If no preferences for document mode are set, the user is not in document mode.
+        sharedPreferencesEditor.remove(DocumentModeAssassin.MIGRATION_ON_UPGRADE_ATTEMPTED);
+        sharedPreferencesEditor.remove(DocumentModeAssassin.OPT_OUT_STATE);
+        sharedPreferencesEditor.apply();
+        assertTrue(DocumentModeAssassin.isOptedOutOfDocumentMode());
+
+        // If the preference for opting out of document mode is set, the user is not in document
+        // mode.
+        sharedPreferencesEditor.remove(DocumentModeAssassin.MIGRATION_ON_UPGRADE_ATTEMPTED);
+        sharedPreferencesEditor.putInt(DocumentModeAssassin.OPT_OUT_STATE,
+                DocumentModeAssassin.OPTED_OUT_OF_DOCUMENT_MODE);
+        sharedPreferencesEditor.apply();
+        assertTrue(DocumentModeAssassin.isOptedOutOfDocumentMode());
+
+        // If the user has been migrated into document mode and no preference has been set for
+        // OPT_OUT_STATE, the user should still be in document mode.
+        sharedPreferencesEditor.putBoolean(DocumentModeAssassin.MIGRATION_ON_UPGRADE_ATTEMPTED,
+                true);
+        sharedPreferencesEditor.remove(DocumentModeAssassin.OPT_OUT_STATE);
+        sharedPreferencesEditor.apply();
+        assertFalse(DocumentModeAssassin.isOptedOutOfDocumentMode());
+
+        // If the user has been migrated into document mode and no preference has been set for
+        // OPT_OUT_STATE, but a "new" tabbed mode metadata file exists, migration has already been
+        // attempted or incorrectly skipped. The user is not in document mode.
+        sharedPreferencesEditor.putBoolean(DocumentModeAssassin.MIGRATION_ON_UPGRADE_ATTEMPTED,
+                true);
+        sharedPreferencesEditor.remove(DocumentModeAssassin.OPT_OUT_STATE);
+        sharedPreferencesEditor.apply();
+        mTabbedModeDirectory.writeTabModelFiles(TestTabModelDirectory.TAB_MODEL_METADATA_V5, false);
+        assertTrue(DocumentModeAssassin.isOptedOutOfDocumentMode());
+    }
+
     /** Creates a DocumentModeAssassin with all of its calls pointing at our mocked classes.
      * @param isMigrationNecessary TODO(dfalcantara):*/
     private DocumentModeAssassinForTesting createAssassinForTesting(