Update: Waiting for the screen capture to verify the root cause. 

Based on the screen capture from partner, it takes about 10 seconds before the dialog popup. One of the solution is displaying the popup before the browser is fully loaded.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87

commit 065fd8ffaebd901b6033aaa5d1d7693c3ff26d87
Author: zmin <zmin@chromium.org>
Date: Tue Jul 26 15:45:11 2016

Improves first run dialog performance on Win8

BUG= 616829 

Review-Url: https://codereview.chromium.org/2090773002
Cr-Commit-Position: refs/heads/master@{#407810}

[modify] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/browser/ui/startup/default_browser_prompt_win.cc
[modify] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
[add] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/browser/ui/webui/set_as_default_browser_ui_browsertest_win.cc
[rename] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/browser/ui/webui/set_as_default_browser_ui_win.cc
[rename] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/browser/ui/webui/set_as_default_browser_ui_win.h
[modify] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/chrome_browser_ui.gypi
[modify] https://crrev.com/065fd8ffaebd901b6033aaa5d1d7693c3ff26d87/chrome/chrome_tests.gypi

This issue has been fixed and verified by the partner. It's being tested manually by TE now. Please merge this into M53 after that so the partner doesn't have to wait for very long time.

Your change meets the bar and is auto-approved for M53 (branch: 2785)

This merge is auto approved by merge approval script. Please merge your change to M53 branch 2785 ONLY after pbommana@ (TE) test/verify the change. Thank you.

pbommana: please update this issue once your testing is complete. Thank you!

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

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I have executed the test cases you provided and haven't seen any issues. Below are details :

Case 1: 
- When Installed Chrome using Standalone installer(M54) welcome windows pop up in center of the screen.

Case 2:
- Tried different x and y coordinates like 10, 50, 100 , 200 and 400, the x, y coordinates are honored and the welcome window pop up at specified locations.


Note : On laptops since the screen size is smaller the Welcome window takes away lot of space which in result any coordinate higher then 50 looks like they are a bit towards center(At least 30% of the window is towards center of the screen with 100 and 150). Please let me know if you want me to check anything else if not we are good to get the CL merge to M53.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647

commit dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647
Author: Greg Thompson <grt@chromium.org>
Date: Tue Aug 16 18:36:49 2016

Improves first run dialog performance on Win8

BUG= 616829 

Review-Url: https://codereview.chromium.org/2090773002
Cr-Commit-Position: refs/heads/master@{#407810}
(cherry picked from commit 065fd8ffaebd901b6033aaa5d1d7693c3ff26d87)
TBR=grt@chromium.org

Review URL: https://codereview.chromium.org/2252793002 .

Cr-Commit-Position: refs/branch-heads/2785@{#627}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}

[modify] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/browser/ui/startup/default_browser_prompt_win.cc
[modify] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
[add] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/browser/ui/webui/set_as_default_browser_ui_browsertest_win.cc
[rename] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/browser/ui/webui/set_as_default_browser_ui_win.cc
[rename] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/browser/ui/webui/set_as_default_browser_ui_win.h
[modify] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/chrome_browser_ui.gypi
[modify] https://crrev.com/dd8fea09d64cb3dcdf5c80bb52a51bfcb26f4647/chrome/chrome_tests.gypi

Verified the same on latest chrome Beta i.e., 53.0.2785.70 and everything looks good.

Adding TE-Verified labels as per comment #13.