Make scrollWidth and scrollHeight match other DOM measurement APIs

Source/core/layout/LayoutTextControlSingleLine.cpp

Index: Source/core/layout/LayoutTextControlSingleLine.cpp
diff --git a/Source/core/layout/LayoutTextControlSingleLine.cpp b/Source/core/layout/LayoutTextControlSingleLine.cpp
index ea0a51c6b1e54f8cee33459444cddfc78e2af6f7..68385b95dbe5999df005aa36e89641a9513e23a8 100644
--- a/Source/core/layout/LayoutTextControlSingleLine.cpp
+++ b/Source/core/layout/LayoutTextControlSingleLine.cpp
@@ -390,7 +390,10 @@ LayoutUnit LayoutTextControlSingleLine::scrollWidth() const
         // Adjust scrollWidth to inculde input element horizontal paddings and
         // decoration width
         LayoutUnit adjustment = clientWidth() - inner->clientWidth();
-        return innerEditorElement()->scrollWidth() + adjustment;
+        // TODO(leviw): We floor to avoid breaking JS that tries to scroll to
+        // scrollWidth - clientWidth.
+        // TODO(leviw): These values are broken when zooming. crbug.com/471412
+        return inner->scrollWidth().floor() + adjustment;
     }
     return LayoutBlockFlow::scrollWidth();
 }
@@ -401,7 +404,10 @@ LayoutUnit LayoutTextControlSingleLine::scrollHeight() const
         // Adjust scrollHeight to include input element vertical paddings and
         // decoration height
         LayoutUnit adjustment = clientHeight() - inner->clientHeight();
-        return innerEditorElement()->scrollHeight() + adjustment;
+        // TODO(leviw): We floor to avoid breaking JS that tries to scroll to
+        // scrollHeight - clientHeight.
+        // TODO(leviw): These values are broken when zooming. crbug.com/471412
+        return inner->scrollHeight().floor() + adjustment;
     }
     return LayoutBlockFlow::scrollHeight();
 }