Note: I would have expected these to be another set of repro steps:
1) Start Chrome with --site-per-process.
2) Visit http://csreis.github.io/tests/blob.html
3) Click "Add iframe with blob URL" button.

The iframe should be in process, but I would expect it to become an out-of-process iframe.  It's unexpectedly staying in process...?

Sounds like Nick's https://codereview.chromium.org/1878273002/ will be one part of the fix.

With the fix mentioned in #2 now landed, we are now seeing this bug in a layouttest: http/tests/fileapi/blob-url-in-subframe.html

I'll fix it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/31d0ea2933c9d8fbeb1c30ff0c34473c7e4784db

commit 31d0ea2933c9d8fbeb1c30ff0c34473c7e4784db
Author: nick <nick@chromium.org>
Date: Mon Apr 18 22:24:31 2016

Update test expectations for blob and bindings check bugs.

BUG= 602818 , 584984 

Review URL: https://codereview.chromium.org/1900853002

Cr-Commit-Position: refs/heads/master@{#388049}

[modify] https://crrev.com/31d0ea2933c9d8fbeb1c30ff0c34473c7e4784db/third_party/WebKit/LayoutTests/FlagExpectations/site-per-process

The remaining part of this fix turns out to be easy: we just need to teach SiteInstance::GetSiteForURL about blobs. We'll want to do the same for filesystem URLs, and we'll get it for free if we use url::Origin.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1dd47922979b128ce7ee8debf138b83c65661024

commit 1dd47922979b128ce7ee8debf138b83c65661024
Author: nick <nick@chromium.org>
Date: Fri Apr 29 16:44:48 2016

Teach SiteInstance::GetSiteForURL() about blob and filesystem URLs.

Use url::Origin to do the heavy lifting.

This fixes FrameTreeBrowsertest.NavigateGrandchildToBlob under --site-per-process, and fixes process transfers for blob URLs in general.

url::Origin extraction exposed a bug where tests encountered chrome-search:// URLs with ports. This is fixed by clearing the port.

BUG= 602818 , 564316 ,490074, 605720 

Review-Url: https://codereview.chromium.org/1911573002
Cr-Commit-Position: refs/heads/master@{#390672}

[modify] https://crrev.com/1dd47922979b128ce7ee8debf138b83c65661024/chrome/browser/search/search.cc
[modify] https://crrev.com/1dd47922979b128ce7ee8debf138b83c65661024/chrome/browser/search/search_unittest.cc
[modify] https://crrev.com/1dd47922979b128ce7ee8debf138b83c65661024/content/browser/site_instance_impl.cc
[modify] https://crrev.com/1dd47922979b128ce7ee8debf138b83c65661024/content/browser/site_instance_impl_unittest.cc
[modify] https://crrev.com/1dd47922979b128ce7ee8debf138b83c65661024/testing/buildbot/filters/site-per-process.content_browsertests.filter

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c95b1fe8a47162538c389ec2361332473437beda

commit c95b1fe8a47162538c389ec2361332473437beda
Author: lukasza <lukasza@chromium.org>
Date: Fri Apr 29 20:14:08 2016

Remove exceptions for tests fixed by teaching GetSiteForURL() about blob URLs.

These tests got recently fixed by https://crrev.com/1911573002

BUG= 602818 

Review-Url: https://codereview.chromium.org/1932273002
Cr-Commit-Position: refs/heads/master@{#390732}

[modify] https://crrev.com/c95b1fe8a47162538c389ec2361332473437beda/third_party/WebKit/LayoutTests/FlagExpectations/site-per-process