Closes #6783: Engine session state is not restored

components/browser/session/src/main/java/mozilla/components/browser/session/storage/SnapshotSerializer.kt

@@ -82,10 +82,11 @@ class SnapshotSerializer(
 
     fun itemFromJSON(engine: Engine, json: JSONObject): SessionManager.Snapshot.Item {
         val sessionJson = json.getJSONObject(Keys.SESSION_KEY)
+        val engineSessionJson = json.getJSONObject(Keys.ENGINE_SESSION_KEY)
         val session = deserializeSession(sessionJson, restoreSessionIds, restoreParentIds)
         val readerState =
             ReaderState(active = sessionJson.optBoolean(Keys.SESSION_READER_MODE_KEY, false))
-        val engineState = engine.createSessionState(sessionJson)
+        val engineState = engine.createSessionState(engineSessionJson)
 
         return SessionManager.Snapshot.Item(
             session,

components/browser/session/src/test/java/mozilla/components/browser/session/storage/SnapshotSerializerTest.kt

@@ -9,6 +9,8 @@ import mozilla.components.browser.session.Session
 import mozilla.components.browser.session.SessionManager.Snapshot
 import mozilla.components.browser.state.state.ReaderState
 import mozilla.components.concept.engine.Engine
+import mozilla.components.concept.engine.EngineSession
+import mozilla.components.concept.engine.EngineSessionState
 import mozilla.components.support.test.any
 import mozilla.components.support.test.mock
 import mozilla.components.support.test.whenever
@@ -16,6 +18,7 @@ import org.json.JSONObject
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertNotEquals
 import org.junit.Assert.assertNull
+import org.junit.Assert.assertSame
 import org.junit.Assert.assertTrue
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -44,6 +47,44 @@ class SnapshotSerializerTest {
         assertEquals("Hello World", restoredSession.title)
     }
 
+    @Test
+    fun `Serialize and deserialize with engine session state`() {
+        val engineSessionState: EngineSessionState = mock()
+        val engineSessionJson = JSONObject().apply { put("state", "test") }
+        val engineSession: EngineSession = mock()
+        whenever(engineSession.saveState()).thenReturn(engineSessionState)
+        whenever(engineSessionState.toJSON()).thenReturn(engineSessionJson)
+
+        val engine: Engine = mock()
+        val restoredEngineSessionState: EngineSessionState = mock()
+        whenever(engine.createSessionState(engineSessionJson)).thenReturn(restoredEngineSessionState)
+
+        val originalSession = Session(
+            "https://www.mozilla.org",
+            source = Session.Source.ACTION_VIEW,
+            id = "test-id",
+            contextId = "test-context-id"
+        ).apply {
+            title = "Hello World"
+        }
+
+        val serializer = SnapshotSerializer()
+        val json = serializer.itemToJSON(
+            Snapshot.Item(
+                originalSession,
+                engineSession = engineSession
+            )
+        )
+        val restoredItem = serializer.itemFromJSON(engine, json)
+
+        assertEquals("https://www.mozilla.org", restoredItem.session.url)
+        assertEquals(Session.Source.RESTORED, restoredItem.session.source)
+        assertEquals("test-id", restoredItem.session.id)
+        assertEquals("test-context-id", restoredItem.session.contextId)
+        assertEquals("Hello World", restoredItem.session.title)
+        assertSame(restoredEngineSessionState, restoredItem.engineSessionState)
+    }
+
     @Test
     fun `Serialize and deserialize session with reader state`() {
         val engine: Engine = mock()