[chromedriver] Use center of first ClientRect when moving mouse to an element.

chrome/test/chromedriver/element_util.cc

Index: chrome/test/chromedriver/element_util.cc
diff --git a/chrome/test/chromedriver/element_util.cc b/chrome/test/chromedriver/element_util.cc
index 9f02b4956cd43e6aef989d993487bdafaf12c483..e8714d3d33ef980e43ef819db7bf1560e687bc5e 100644
--- a/chrome/test/chromedriver/element_util.cc
+++ b/chrome/test/chromedriver/element_util.cc
@@ -577,14 +577,21 @@ Status ScrollElementIntoView(
     Session* session,
     WebView* web_view,
     const std::string& id,
+    const WebPoint* offset,
     WebPoint* location) {
-  WebSize size;
-  Status status = GetElementSize(session, web_view, id, &size);
+  WebRect region;
+  Status status = GetElementRegion(session, web_view, id, &region);

[stgao, 2015/01/14 01:47:20]

Not sure if there will be side-effect on screenshot or the like. What's the
difference between GetElementRegion and GetElementSize?

[samuong, 2015/01/14 04:35:05]

GetElementRegion gets a WebRect (i.e. both a WebPoint and a WebSize), and
GetElementSize just gets a WebSize. There are edge cases where these functions
fall back to other behavior, but this is what they do in the usual case:

The size of the size from GetElementSize() is the size of the whole element's
bounding box (as determined by getBoundingClientRects()) while the size from
GetElementRegion() is just the size of the first ClientRect from
getClientRects().

The WebPoint from GetElementRegion is the top-left corner of the first
ClientRect, relative to the top-left corner of the bounding box.

I think there's scope to simplify this, but I want to wait until after the spec
is more concrete on how to handle this.

   if (status.IsError())
     return status;
-  return ScrollElementRegionIntoView(
-      session, web_view, id, WebRect(WebPoint(0, 0), size),
+  status = ScrollElementRegionIntoView(session, web_view, id, region,
       false /* center */, std::string(), location);
+  if (status.IsError())
+    return status;
+  if (offset)
+    location->Offset(offset->x, offset->y);
+  else
+    location->Offset(region.size.width / 2, region.size.height / 2);

[stgao, 2015/01/14 01:47:20]

It may worth a check if this change has unexpected side-effect, because it
changed the returned location of this function (compared to without this patch).

[samuong, 2015/01/14 04:35:05]

I will be running some presubmits later to find as many of these as possible.

+  return Status(kOk);
 }
 
 Status ScrollElementRegionIntoView(