[chromedriver] Make GetElementLocationInView return the top-left coordinate rather than the center

chrome/test/chromedriver/element_util.h

 // Copyright (c) 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 CHROME_TEST_CHROMEDRIVER_ELEMENT_UTIL_H_
 #define CHROME_TEST_CHROMEDRIVER_ELEMENT_UTIL_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 109 matching lines @@
     Session* session,
     WebView* web_view,
     const std::string& element_id,
     bool selected);
 
 Status ToggleOptionElement(
     Session* session,
     WebView* web_view,
     const std::string& element_id);
 
+// |offset| is an optional offset from the top-left of the first ClientRect
+// that is returned by the element's getClientRects() function.
+// If |offset| is null, the |location| returned will be the center of the
+// ClientRect. If it is non-null, |location| will be offset by the specified
+// value.
 Status ScrollElementIntoView(
     Session* session,
     WebView* web_view,
     const std::string& element_id,
     const WebPoint* offset,
     WebPoint* location);
 
 // |element_id| refers to the element which is to be scrolled into view.
 // |clickable_element_id| refers to the element needing clickable verification.
 // They are usually the same, but can be different. This is useful when an image
 // uses map/area. The image is scrolled, but check clickable against the area.
 // If |clickable_element_id| is "", no verification will be performed.
 Status ScrollElementRegionIntoView(
     Session* session,
     WebView* web_view,
     const std::string& element_id,
     const WebRect& region,
     bool center,
     const std::string& clickable_element_id,
     WebPoint* location);
 
 #endif  // CHROME_TEST_CHROMEDRIVER_ELEMENT_UTIL_H_