Use float for scroll offset.

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

Index: third_party/WebKit/Source/core/testing/Internals.h
diff --git a/third_party/WebKit/Source/core/testing/Internals.h b/third_party/WebKit/Source/core/testing/Internals.h
index f44de15da9eefb205bc0d232251fd3c9a762ad4a..3abe5bda1f794c53ad8eed17557139a6d2426c0d 100644
--- a/third_party/WebKit/Source/core/testing/Internals.h
+++ b/third_party/WebKit/Source/core/testing/Internals.h
@@ -484,8 +484,8 @@ class Internals final : public GarbageCollectedFinalized<Internals>,
   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.