This part of code haven't been touched for some time. And the flakiness seems only happen on browser_side_navigation_browser_tests
+clamy@ + csharrison@ for awareness.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5fcb1d027815fa0bc6f93ad2005b947c37187701

commit 5fcb1d027815fa0bc6f93ad2005b947c37187701
Author: Xida Chen <xidachen@chromium.org>
Date: Fri Jun 23 14:33:39 2017

Disable flaky test SubFrameDirectDownload

TBR=msramek@chromium.org
NOTRY=true

Bug:  736354 
Change-Id: I4d6ddca7c5cb167d6f39da22a63fba7eac54e00e
Reviewed-on: https://chromium-review.googlesource.com/545735
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#481879}
[modify] https://crrev.com/5fcb1d027815fa0bc6f93ad2005b947c37187701/chrome/browser/safe_browsing/safe_browsing_navigation_observer_browsertest.cc

FYI SBNavigationObserverBrowserTest.SubFrameNewTabDownload is also flaky. I will disable it.

Sample failure: https://uberchromegw.corp.google.com/i/chromium.win/builders/Win10%20Tests%20x64/builds/13689

Output:
[ RUN      ] SBNavigationObserverBrowserTest.SubFrameNewTabDownload
[8032:3084:0707/130403.843:WARNING:chrome_browser_main_win.cc(469)] Command line too long for RegisterApplicationRestart:  --brave-new-test-launcher --cfi-diag=0 --enable-browser-side-navigation --gtest_also_run_disabled_tests --gtest_filter=SBNavigationObserverBrowserTest.SubFrameNewTabDownload --single_process --test-launcher-bot-mode --test-launcher-summary-output="e:\b\s\w\io9vnywr\output.json" --user-data-dir="C:\Users\CHROME~2\AppData\Local\Temp\scoped_dir1816_16525\d1816_8068" --disable-offline-auto-reload --disable-features=NetworkPrediction --no-first-run --no-default-browser-check --enable-logging=stderr --log-level=0 --safebrowsing-disable-auto-update --disable-default-apps --wm-window-animations-disabled --disable-component-update --test-type=browser --force-color-profile=srgb --disable-zero-browsers-open-for-tests --ipc-connection-timeout=30 --allow-file-access-from-files --dom-automation --log-gpu-control-list-decisions --disable-backgrounding-occluded-windows --disable-gl-drawing-for-tests --override-use-software-gl-for-tests --force-color-profile=srgb --flag-switches-begin --flag-switches-end --restore-last-session about:blank
[8032:7752:0707/130404.854:WARNING:embedded_test_server.cc(219)] Request not handled. Returning 404: /favicon.ico
c:\b\c\b\win\src\chrome\browser\safe_browsing\safe_browsing_navigation_observer_browsertest.cc(310): error:       Expected: expected_original_request_url
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe.html
To be equal to: actual_nav_event->original_request_url
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe_retargeting.html
c:\b\c\b\win\src\chrome\browser\safe_browsing\safe_browsing_navigation_observer_browsertest.cc(311): error:       Expected: expected_destination_url
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe.html
To be equal to: actual_nav_event->GetDestinationUrl()
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe_retargeting.html
c:\b\c\b\win\src\chrome\browser\safe_browsing\safe_browsing_navigation_observer_browsertest.cc(310): error:       Expected: expected_original_request_url
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe_retargeting.html
To be equal to: actual_nav_event->original_request_url
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe.html
c:\b\c\b\win\src\chrome\browser\safe_browsing\safe_browsing_navigation_observer_browsertest.cc(311): error:       Expected: expected_destination_url
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe_retargeting.html
To be equal to: actual_nav_event->GetDestinationUrl()
      Which is: http://127.0.0.1:60971/safe_browsing/download_protection/navigation_observer/iframe.html
[  FAILED  ] SBNavigationObserverBrowserTest.SubFrameNewTabDownload, where TypeParam =  and GetParam() =  (1215 ms)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f96ed3043048c120df44fd49baea9486546b41a7

commit f96ed3043048c120df44fd49baea9486546b41a7
Author: Bret Sepulveda <bsep@chromium.org>
Date: Fri Jul 07 21:31:13 2017

Disable SBNavigationObserverBrowserTest.SubFrameNewTabDownload on Win.

Test has been flaky in browser_side_navigation_browser_tests on the
Win10 x64 builder.

TBR=jialiul@chromium.org

Bug:  736354 
Change-Id: I0c08342b573df0b839e007b02d8d6509a831d20a
Reviewed-on: https://chromium-review.googlesource.com/563770
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485055}
[modify] https://crrev.com/f96ed3043048c120df44fd49baea9486546b41a7/chrome/browser/safe_browsing/safe_browsing_navigation_observer_browsertest.cc

csharrison -- Please take a look and let us know if it needs SafeBrowsing team's input.

Sorry, I don't have time to fix these right now.

The other SB download issues fixed involved using a download observer to wait until the download is finished. See calls to DownloadItemCreatedObserver::WaitForDownloadItem for more details.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e95247e5b22ad18642c7e4b73dad42450089dc5a

commit e95247e5b22ad18642c7e4b73dad42450089dc5a
Author: Jialiu Lin <jialiul@chromium.org>
Date: Wed Aug 02 16:29:11 2017

Fix Flacky tests in SBNavigationObserverBrowserTest

Fix flacky tests in SBNavigationObserverBrowserTest is caused by the
non-deterministic iframe navigation order. This CL add checks to both
possible orders.

Bug:  739716 , 736354 
Change-Id: I0b256d492500b8f2872485235eb0b826dae6c827
Reviewed-on: https://chromium-review.googlesource.com/594711
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Reviewed-by: Luke Z <lpz@chromium.org>
Commit-Queue: Jialiu Lin <jialiul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491398}
[modify] https://crrev.com/e95247e5b22ad18642c7e4b73dad42450089dc5a/chrome/browser/safe_browsing/safe_browsing_navigation_observer_browsertest.cc