Make AW state_serializer handle restoring also legacy format

android_webview/native/state_serializer.h

Index: android_webview/native/state_serializer.h
diff --git a/android_webview/native/state_serializer.h b/android_webview/native/state_serializer.h
index b220ccfb5f0119c7aa184f9db589f7cdbc0b8fa9..644d5ccaa459e945fb036ba3377c6b37586987d2 100644
--- a/android_webview/native/state_serializer.h
+++ b/android_webview/native/state_serializer.h
@@ -5,6 +5,8 @@
 #ifndef ANDROID_WEBVIEW_NATIVE_STATE_SERIALIZER_H_
 #define ANDROID_WEBVIEW_NATIVE_STATE_SERIALIZER_H_
 
+#include <cstdint>
+
 #include "base/compiler_specific.h"
 
 namespace base {
@@ -37,16 +39,30 @@ bool RestoreFromPickle(base::PickleIterator* iterator,
 
 namespace internal {
 
-// Functions below are individual helper functiosn called by functions above.
+const uint32_t AW_STATE_VERSION_INITIAL = 20130814;
+const uint32_t AW_STATE_VERSION_DATA_URL = 20151204;
+
+// Functions below are individual helper functions called by functions above.
 // They are broken up for unit testing, and should not be called out side of
 // tests.
 bool WriteHeaderToPickle(base::Pickle* pickle) WARN_UNUSED_RESULT;
-bool RestoreHeaderFromPickle(base::PickleIterator* iterator) WARN_UNUSED_RESULT;
+bool WriteHeaderToPickle(uint32_t state_version,
+                         base::Pickle* pickle) WARN_UNUSED_RESULT;
+uint32_t RestoreHeaderFromPickle(base::PickleIterator* iterator)
+    WARN_UNUSED_RESULT;
+bool IsSupportedVersion(uint32_t state_version) WARN_UNUSED_RESULT;
 bool WriteNavigationEntryToPickle(const content::NavigationEntry& entry,
                                   base::Pickle* pickle) WARN_UNUSED_RESULT;
-bool RestoreNavigationEntryFromPickle(
-    base::PickleIterator* iterator,
-    content::NavigationEntry* entry) WARN_UNUSED_RESULT;
+bool WriteNavigationEntryToPickle(uint32_t state_version,
+                                  const content::NavigationEntry& entry,
+                                  base::Pickle* pickle) WARN_UNUSED_RESULT;
+bool RestoreNavigationEntryFromPickle(base::PickleIterator* iterator,
+                                      content::NavigationEntry* entry)
+    WARN_UNUSED_RESULT;
+bool RestoreNavigationEntryFromPickle(uint32_t state_version,
+                                      base::PickleIterator* iterator,
+                                      content::NavigationEntry* entry)
+    WARN_UNUSED_RESULT;
 
 }  // namespace interanl