Align the base of the shelf's context menu to the top edge of the shelf.

chrome/browser/ui/window_sizer/window_sizer_ash_uitest.cc

 // Copyright 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.
 
 #include "ash/shelf/shelf_view.h"
 #include "ash/shelf/wm_shelf.h"
 #include "ash/shell.h"
 #include "ash/wm_window.h"
 #include "base/command_line.h"
 #include "base/location.h"
@@ skipping 145 matching lines @@
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WindowSizerContextMenuTest);
 };
 
 void OpenBrowserUsingContextMenuOnRootWindow(aura::Window* root_window) {
   gfx::Point chrome_icon =
       GetChromeIconBoundsForRootWindow(root_window).CenterPoint();
   gfx::Point release_point = chrome_icon;
-  release_point.Offset(50, -120);
+  // 50 is the distance from the chrome icon to leftest of the screen.

[msw, 2017/05/10 22:18:23]

nit: s/leftest/the left edge/. Also, I'm not sure if this is accurate... why
would we need to offset the release point's x value by the distance between the
chrome icon and the left edge of the screen, if the x value is from
|chrome_icon|, which is already presumably the x-coordinate of the icon (the
distance between the icon and the left edge of the screen). Perhaps this
x-offset isn't needed?

[minch1, 2017/05/11 16:34:03]

This is only my own understanding, I didn't check this with the owner of this
line? I tried to make it as 0 locally, the UT passed locally. If Trybot results
are all agree here, does that means it is ok to make it as 0 here?

[msw, 2017/05/11 17:13:39]

Yeah, 0 sgtm; thanks for simplifying this mystifying value.

+  // -153 moves from the chrome icon to the "New window" in the opened context

[msw, 2017/05/10 22:18:23]

nit: // -153 moves the cursor up to the "New window" menu option.

+  // menu.
+  release_point.Offset(50, -153);
   ui_controls::SendMouseMoveNotifyWhenDone(
       chrome_icon.x(), chrome_icon.y(),
       base::Bind(&WindowSizerContextMenuTest::Step1, release_point));
   base::RunLoop().Run();
 }
 
 }  // namespace
 
 IN_PROC_BROWSER_TEST_F(WindowSizerContextMenuTest,
                        MAYBE_OpenBrowserUsingContextMenuOnOtherDisplay) {
@@ skipping 21 matching lines @@
 
   CloseBrowser(browser_list->get(0));
   OpenBrowserUsingContextMenuOnRootWindow(root_windows[0]);
 
   // Next new browser must be created on 1st display.
   ASSERT_EQ(1u, browser_list->size());
   EXPECT_EQ(root_windows[0],
             browser_list->get(0)->window()->GetNativeWindow()->GetRootWindow());
   EXPECT_EQ(root_windows[0], ash::Shell::GetRootWindowForNewWindows());
 }