Add DidSaveScrollOrScaleState flag to prevent restoreScrollPositionAndViewState restore from default

content/common/page_state_serialization.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_COMMON_PAGE_STATE_SERIALIZATION_H_
 #define CONTENT_COMMON_PAGE_STATE_SERIALIZATION_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 26 matching lines @@
   base::NullableString16 referrer;
   base::NullableString16 target;
   base::NullableString16 state_object;
   std::vector<base::NullableString16> document_state;
   blink::WebHistoryScrollRestorationType scroll_restoration_type;
   gfx::PointF visual_viewport_scroll_offset;
   gfx::Point scroll_offset;
   int64_t item_sequence_number;
   int64_t document_sequence_number;
   double page_scale_factor;
+  bool did_save_scroll_state;
   blink::WebReferrerPolicy referrer_policy;
   ExplodedHttpBody http_body;
   std::vector<ExplodedFrameState> children;
 
   ExplodedFrameState();
   ExplodedFrameState(const ExplodedFrameState& other);
   ~ExplodedFrameState();
   void operator=(const ExplodedFrameState& other);
 
 private:
@@ skipping 31 matching lines @@
     size_t size);
 
 // Encodes |resource_request_body| into |encoded|.
 std::string EncodeResourceRequestBody(
     const ResourceRequestBodyImpl& resource_request_body);
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_PAGE_STATE_SERIALIZATION_H_