Fix crash when openerAppId is null in CriticalPersistedTabData

Protocol buffers do not allow fields to be null so openerAppId is
converted to an empty string if it is null on serialize() and then
converted back again on deserialize().

Bug: 1161980
Change-Id: Id0cedad8b47b1f40938c934536c18769d874ca71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2611899Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Commit-Queue: David Maunder <davidjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840448}

chrome/android/javatests/src/org/chromium/chrome/browser/tab/state/CriticalPersistedTabDataTest.java

@@ -252,4 +252,20 @@ public class CriticalPersistedTabDataTest {
                 CriticalPersistedTabData.getContentStateByteArray(
                         deserialized.getWebContentsState().buffer()));
     }
+
+    @UiThreadTest
+    @SmallTest
+    @Test
+    public void testOpenerAppIdNull() {
+        Tab tab = mockTab(TAB_ID, false);
+        CriticalPersistedTabData criticalPersistedTabData = new CriticalPersistedTabData(tab, "",
+                "", PARENT_ID, ROOT_ID, TIMESTAMP, WEB_CONTENTS_STATE, CONTENT_STATE_VERSION, null,
+                THEME_COLOR, LAUNCH_TYPE_AT_CREATION);
+        byte[] serialized = criticalPersistedTabData.serialize();
+        PersistedTabDataConfiguration config = PersistedTabDataConfiguration.get(
+                ShoppingPersistedTabData.class, tab.isIncognito());
+        CriticalPersistedTabData deserialized =
+                new CriticalPersistedTabData(tab, serialized, config.getStorage(), config.getId());
+        Assert.assertEquals(null, deserialized.getOpenerAppId());
+    }
 }

chrome/browser/tab/java/src/org/chromium/chrome/browser/tab/state/CriticalPersistedTabData.java

@@ -225,7 +225,9 @@ public class CriticalPersistedTabData extends PersistedTabData {
                     : new GURL(mWebContentsState.getVirtualUrlFromState());
             mTitle = mWebContentsState.getDisplayTitleFromState();
             mContentStateVersion = criticalPersistedTabDataProto.getContentStateVersion();
-            mOpenerAppId = criticalPersistedTabDataProto.getOpenerAppId();
+            mOpenerAppId = TextUtils.isEmpty(criticalPersistedTabDataProto.getOpenerAppId())
+                    ? null
+                    : criticalPersistedTabDataProto.getOpenerAppId();
             mThemeColor = criticalPersistedTabDataProto.getThemeColor();
             mTabLaunchTypeAtCreation =
                     getLaunchType(criticalPersistedTabDataProto.getLaunchTypeAtCreation());
@@ -369,7 +371,7 @@ public class CriticalPersistedTabData extends PersistedTabData {
                                     : ByteString.copyFrom(
                                             getContentStateByteArray(webContentsState.buffer())))
                     .setContentStateVersion(mContentStateVersion)
-                    .setOpenerAppId(mOpenerAppId)
+                    .setOpenerAppId(mOpenerAppId == null ? "" : mOpenerAppId)
                     .setThemeColor(mThemeColor)
                     .setLaunchTypeAtCreation(getLaunchType(mTabLaunchTypeAtCreation))
                     .build()