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

Previously we used the center of the bounding box, but this can cause problems if the center of the bounding box is outside the element.

This CL also changes the behavior of the GetElementLocationOnceScrolledIntoView command in the same way.

BUG=

Review URL: https://codereview.chromium.org/848483002

Cr-Commit-Position: refs/heads/master@{#311423}

chrome/test/chromedriver/element_commands.cc

@@ -445,7 +445,7 @@ Status ExecuteGetElementLocationOnceScrolledIntoView(
     scoped_ptr<base::Value>* value) {
   WebPoint location;
   Status status = ScrollElementIntoView(
-      session, web_view, element_id, &location);
+      session, web_view, element_id, nullptr, &location);
   if (status.IsError())
     return status;
   value->reset(CreateValueFrom(location));

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);
   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);
+  return Status(kOk);
 }
 
 Status ScrollElementRegionIntoView(

chrome/test/chromedriver/element_util.h

@@ -131,6 +131,7 @@ 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.

chrome/test/chromedriver/test/run_py_tests.py

@@ -571,6 +571,29 @@ class ChromeDriverTest(ChromeDriverBaseTest):
     self._driver.MouseMoveTo(div, 10, 10)
     self.assertEquals(1, len(self._driver.FindElements('tag name', 'br')))
 
+  def testMoveToElementAndClick(self):
+    self._driver.Load(self.GetHttpUrlForFile('/chromedriver/multiline.html'))
+
+    # Check that link element spans two lines and that the first ClientRect is
+    # above the second.
+    link = self._driver.FindElements('tag name', 'a')[0]
+    client_rects = self._driver.ExecuteScript(
+        'return arguments[0].getClientRects();', link)
+    self.assertEquals(2, len(client_rects))
+    self.assertTrue(client_rects[0]['bottom'] < client_rects[1]['top'])
+
+    # Check that the center of the link's bounding ClientRect is outside the
+    # element.
+    bounding_client_rect = self._driver.ExecuteScript(
+        'return arguments[0].getBoundingClientRect();', link)
+    center = bounding_client_rect['left'] + bounding_client_rect['width'] / 2
+    self.assertTrue(client_rects[1]['right'] < center)
+    self.assertTrue(center < client_rects[0]['left'])
+
+    self._driver.MouseMoveTo(link)
+    self._driver.MouseClick()
+    self.assertTrue(self._driver.GetCurrentUrl().endswith('#top'))
+
   def testMouseClick(self):
     div = self._driver.ExecuteScript(
         'document.body.innerHTML = "<div>old</div>";'

chrome/test/chromedriver/window_commands.cc

@@ -470,22 +470,15 @@ Status ExecuteMouseMoveTo(
 
   WebPoint location;
   if (has_element) {
-    Status status = ScrollElementIntoView(
-        session, web_view, element_id, &location);
+    WebPoint offset(x_offset, y_offset);
+    Status status = ScrollElementIntoView(session, web_view, element_id,
+        has_offset ? &offset : nullptr, &location);
     if (status.IsError())
       return status;
   } else {
     location = session->mouse_position;
-  }
-
-  if (has_offset) {
-    location.Offset(x_offset, y_offset);
-  } else {
-    WebSize size;
-    Status status = GetElementSize(session, web_view, element_id, &size);
-    if (status.IsError())
-      return status;
-    location.Offset(size.width / 2, size.height / 2);
+    if (has_offset)
+      location.Offset(x_offset, y_offset);
   }
 
   std::list<MouseEvent> events;

chrome/test/data/chromedriver/multiline.html

+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>A multi-line link</title>
+  </head>
+  <body>
+    <p style="max-width: 11em">
+      This test page contains <a href="#top">a link</a> that spans two lines.
+      The center of the bounding box of the link is not inside the link element.
+    </p>
+  </body>
+</html>