Use float for scroll offset.

third_party/WebKit/Source/core/testing/Internals.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 466 matching lines @@
   //       Normal LayoutTests should use gc() instead as it would trigger both Blink GC and V8 GC.
   void forceBlinkGCWithoutV8GC();
 
   String selectedHTMLForClipboard();
   String selectedTextForClipboard();
 
   void setVisualViewportOffset(int x, int y);
   int visualViewportHeight();
   int visualViewportWidth();
   // The scroll position of the visual viewport relative to the document origin.
-  double visualViewportScrollX();
-  double visualViewportScrollY();
+  float visualViewportScrollX();
+  float visualViewportScrollY();
 
   // Return true if the given use counter exists for the given document.
   // |useCounterId| must be one of the values from the UseCounter::Feature enum.
   bool isUseCounted(Document*, int useCounterId);
   bool isCSSPropertyUseCounted(Document*, const String&);
 
   String unscopableAttribute();
   String unscopableMethod();
 
   ClientRectList* focusRingRects(Element*);
@@ skipping 38 matching lines @@
                            unsigned index,
                            ExceptionState&);
   Member<InternalRuntimeFlags> m_runtimeFlags;
 
   IterationSource* startIteration(ScriptState*, ExceptionState&) override;
 };
 
 }  // namespace blink
 
 #endif  // Internals_h