Slapping some aggressive Blink labels on it, in the hopes that someone who knows the Blob implementation can chime in. I assume Blink>FileAPI should be sufficient, but since Storage & <file> also use it, there may be knowledge there.

Blink>FileAPI is sufficient, we triage/own both (it should maybe be Blink>Storage>FileAPI)

Tried creating the html file from the provided Document and clicking the link does not downloads any file. It gives the following error in console(Screen Shot provided).

Could some one please guide us for the same.

Thanks.!

Deleted: Screen Shot 2016-03-18 at 1.23.18 PM.png 177 KB

	Screen Shot 2016-03-18 at 1.23.18 PM.png 177 KB View Download

Hi, the html file(s) needs to be uploaded to a web server. Upon opening the html file named downloadFile_Pass.html in Chrome and the clicking the link the html file itself is downloaded. In the case of downloadFile_Fail.html the "Failed - No file" error is shown.  thanks for looking into this.

Deleted: downloadFile_Fail.html 982 bytes

downloadFile_Fail.html 982 bytes View Download

Deleted: downloadFile_Pass.html 984 bytes

downloadFile_Pass.html 984 bytes View Download

Addition to comment 6.
I have uploaded the files to a web server. Please see:
http://www.iq-solutions.nl/downloadFile_Fail.html
http://www.iq-solutions.nl/downloadFile_Pass.html
thanks

Thank you for providing more feedback. Assigning to requester "ranjitkan@chromium.org" for another review.

For more details visit https://sites.google.com/a/chromium.org/dev/issue-tracking/autotriage - Your friendly Sheriffbot

Thanks for the details provided. I was able to download both the files from the above two links on build "50.0.2661.37" Beta and Canary - 51.0.2686.0. Same result is observed on Stable 49.0.2623.87.

And please let us know what is that we need to verify under "chrome://blob-internals/"

A screen shot would be more helpful.

Thanks.!

Hi, please find attached a Word file with the requested details. 
Clicking on the link "download current file" after opening the file  downloadFile_Fail.html results in an error "Failed - No File" on Chrome 50. This works fine on Chrome 49. 
Note: the download of the blob is handled through mimicing a mouse event. Any chance that is now done asynchronously in v50?
thanks

Deleted: Test findings Chrome bug 595305 21-03-2016.docx 272 KB

Test findings Chrome bug 595305 21-03-2016.docx 272 KB Download

Thanks a lot for the details provided. Able to reproduce the issue on Windows, MAC 10.11.3, Ubuntu 14.04 and is a regression broken in M50 builds. below are bisect details for the same.

Bisect info:
============
50.0.2634.0 - Good build
50.0.2635.0 - Bad build

Bisect URL: https://chromium.googlesource.com/chromium/src/+log/eac0ccddbbc380e8960228a7989e31a8135fa209..3c4b22daaa8bc6f5ea7da25af0b7c1a7aa957b09

Suspecting the below change could be the possible suspect:

https://chromium.googlesource.com/chromium/src/+/bb028fc67f0835b30bd2ce5d953caa101c15c961

Review URL: https://codereview.chromium.org/1644743003

@asanka: Request you to please take a look into it. Please help us to reassign if not with respect to your change.

The CL mentioned in #11 affects the timing between the download "starting" and the time at which revokeObjectURL() effectively releases the Blob URL. If the download start prior to revokeObjectURL(), then ResourceDispatcherHostImpl will obtain a handle to the blob data and attach it to the URLRequest via a UserData object. If the download loses the race, then the blob would no longer be around by the time ResourceDispatcherHostImpl looks at blob storage.

That said, I'm not sure whether the browser should offer the guarantee that dispatching a click event on an anchor with @download gives the impression of starting synchronously to the extent that revoking the URL immediately afterwards is inconsequential.

Does the DownloadUrl message get sent prior to return from dispatching the click event in blink? If so, it'd be straightforward to grab a blobhandle in DownloadUrl and to include it in the DownloadUrlParameters.

I think that might be necessary even if the message is not sent prior to return from dispatching the click event, although if the ipc is deferred that change is insufficient.

#13: yeah, we can get a BlobHandle and pass it along with the DownloadUrlParameters at the point when the renderer receives the DownloadUrl IPC on the IO thread.

https://codereview.chromium.org/1829413002

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6150c52a037d3b05eeac0faaf792ab0203b5580f

commit 6150c52a037d3b05eeac0faaf792ab0203b5580f
Author: asanka <asanka@chromium.org>
Date: Fri Mar 25 21:40:57 2016

[Downloads] Retain a BlobDataHandle in DownloadUrlParameters.

This allows a caller to extend the lifetime of a blob until the
downloads / resource loader subsystems take over. Without this, an
unfortunately timed revokeObjectURL() call from the originating page may
invalidate the URL before the download has a chance to start the
associated download request.

BUG= 595305 

Review URL: https://codereview.chromium.org/1829413002

Cr-Commit-Position: refs/heads/master@{#383370}

[modify] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/browser/download/download_browsertest.cc
[modify] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/browser/download/download_manager_impl.cc
[modify] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/browser/loader/resource_dispatcher_host_impl.cc
[modify] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/browser/renderer_host/render_message_filter.cc
[modify] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/public/browser/download_url_parameters.h
[add] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/test/data/download/download-attribute-blob.html
[add] https://crrev.com/6150c52a037d3b05eeac0faaf792ab0203b5580f/content/test/data/download/download-attribute-blob.html.mock-http-headers

I'll wait for a Canary or two before requesting a merge.

Requesting merge. This regression dates back to crrev.com/bb028fc67f0835b30bd2ce5d953caa101c15c961 which was pulled into M50.

The change has baked in Canary over the weekend and introduced no new crashes.

Your change meets the bar and is auto-approved for M50 (branch: 2661)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/58242aeb11363fe0436724aefdc56faaf53321e4

commit 58242aeb11363fe0436724aefdc56faaf53321e4
Author: Asanka Herath <asanka@chromium.org>
Date: Mon Mar 28 15:38:42 2016

[Merge M50] [Downloads] Retain a BlobDataHandle in DownloadUrlParameters.

This allows a caller to extend the lifetime of a blob until the
downloads / resource loader subsystems take over. Without this, an
unfortunately timed revokeObjectURL() call from the originating page may
invalidate the URL before the download has a chance to start the
associated download request.

BUG= 595305 

Review URL: https://codereview.chromium.org/1829413002

Cr-Commit-Position: refs/heads/master@{#383370}
(cherry picked from commit 6150c52a037d3b05eeac0faaf792ab0203b5580f)

Review URL: https://codereview.chromium.org/1835913002 .

Cr-Commit-Position: refs/branch-heads/2661@{#403}
Cr-Branched-From: ef6f6ae5e4c96622286b563658d5cd62a6cf1197-refs/heads/master@{#378081}

[modify] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/browser/download/download_browsertest.cc
[modify] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/browser/download/download_manager_impl.cc
[modify] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/browser/loader/resource_dispatcher_host_impl.cc
[modify] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/browser/renderer_host/render_message_filter.cc
[modify] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/public/browser/download_url_parameters.h
[add] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/test/data/download/download-attribute-blob.html
[add] https://crrev.com/58242aeb11363fe0436724aefdc56faaf53321e4/content/test/data/download/download-attribute-blob.html.mock-http-headers

 Issue 597003  has been merged into this issue.

Tested the issue on windows 7, Linux Ubuntu 14.04 and Mac 10.11.3 using chrome version 50.0.2661.57.
Not observed the error "Failed - No File" when clicked on "download current file" from downloadFile_Fail.html.
Please find the attached screen cast for the same.

adding TE-Verified

Deleted: 595305.mp4 530 KB

595305.mp4 530 KB Download