The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/71566dac0210ce08ea01c50bfc73335bfd188c58

commit 71566dac0210ce08ea01c50bfc73335bfd188c58
Author: Joy Ming <jming@chromium.org>
Date: Wed Jan 10 20:57:12 2018

[Downloads ukm] Persist unique UKM ID and source ID.

In order to ensure that there is a unique ID for each download and that
the source ID is retrieved from the web contents, it is necessary to
persist that information in the cache that stores information about
in-progress downloads, even across interruptions and resumptions.

All downloads that have WebContents will pass through
DownloadResourceHandler, which will pass a DownloadCreateInfo to
DownloadManager through the StartDownload call. This ensures that
every download that goes through this path will have a corresponding
entry in InProgressCache, which it owns, with a UKM ID and Source ID.
Later, when UKM is implemented, these can be looked up using the GUID.

However, there are cases where the download is started without
WebContents. Those cases will still maintain an entry with a unique ID
for UKM. However, they will keep a null SourceID to be later processed.

Bug:  785557 
Change-Id: I77fd867d68819f47479ad9ab84edcf3d16d94369
Reviewed-on: https://chromium-review.googlesource.com/828200
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Joy Ming <jming@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528418}
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/BUILD.gn
[add] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/DEPS
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/download_entry.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/download_entry.h
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/in_progress_cache_impl_unittest.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/in_progress_conversions.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/in_progress_conversions_unittest.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/components/download/downloader/in_progress/proto/download_entry.proto
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/BUILD.gn
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_create_info.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_create_info.h
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_manager_impl.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_manager_impl.h
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_resource_handler.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_resource_handler.h
[add] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_ukm_helper.cc
[add] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/download_ukm_helper.h
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/content/browser/download/save_package.cc
[modify] https://crrev.com/71566dac0210ce08ea01c50bfc73335bfd188c58/services/metrics/public/cpp/ukm_recorder.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/123e66ca4d38c7a180c1482511c3a18f28ae6073

commit 123e66ca4d38c7a180c1482511c3a18f28ae6073
Author: Joy Ming <jming@chromium.org>
Date: Mon Jan 29 22:00:18 2018

[Downloads ukm] Initial implementation.

Begin implementation for downloads by creating entries in ukm.xml and
a DownloadUkmHelper following go/downloads-ukm for:
- Download.Started: file_type, download_source
- Download.Interrupted: change_in_file_size, reason,
resulting_file_size, time_since_start
- Download.Resumed: mode, time_since_start
- Download.Completed: resulting_file_size, time_since_start

The implementation strategy is to have a ukm_download_id persisted
that will uniquely identify each download. The ukm_source_id will be
reported only at the start of the download.

Bug:  785557 
Change-Id: I94b46bc3287fcde949e58424dc929e71cec7df16
Reviewed-on: https://chromium-review.googlesource.com/742357
Commit-Queue: Joy Ming <jming@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532613}
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/BUILD.gn
[add] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_content.h
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_item_impl.cc
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_item_impl.h
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_stats.cc
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_stats.h
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_ukm_helper.cc
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_ukm_helper.h
[add] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/download_ukm_helper_unittest.cc
[add] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/browser/download/resume_mode.h
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/content/test/BUILD.gn
[modify] https://crrev.com/123e66ca4d38c7a180c1482511c3a18f28ae6073/tools/metrics/ukm/ukm.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4a8fc9da53e66db1c6aa7812114fb40812a93d49

commit 4a8fc9da53e66db1c6aa7812114fb40812a93d49
Author: Joy Ming <jming@chromium.org>
Date: Wed Mar 07 01:30:56 2018

[Downloads ukm] Add bytes wasted metrics.

Bytes wasted measures the number of bytes used beyond the file size,
often as a result of resumptions. Before the in-progress cache, there
was no way of maintaining the number of bytes wasted across resumptions
on the native side even though Java uses SharedPreferences to do so in
DownloadManagerService.updateBytesReceived. This CL implements the bytes
wasted count on native utilizing the in-progress cache and reporting
these metrics through UKM.

Bug:  785557 
Change-Id: I79614f1f4fab73d0e526c096e3f68541f7cb1170
Reviewed-on: https://chromium-review.googlesource.com/909288
Commit-Queue: Joy Ming <jming@chromium.org>
Reviewed-by: Min Qin <qinmin@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541263}
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/downloader/in_progress/download_entry.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/downloader/in_progress/download_entry.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/downloader/in_progress/in_progress_conversions.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/downloader/in_progress/in_progress_conversions_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/downloader/in_progress/proto/download_entry.proto
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/internal/common/base_file.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/internal/common/base_file_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/internal/common/base_file_win_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/internal/common/download_ukm_helper.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/internal/common/download_ukm_helper_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/public/common/base_file.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/public/common/download_item.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/components/download/public/common/download_ukm_helper.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/devtools/protocol/devtools_protocol_browsertest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_browsertest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_file.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_file_impl.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_file_impl.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_file_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_item_impl.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_item_impl.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_item_impl_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_job.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_job.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/download_manager_impl.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/mock_download_file.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/mock_download_file.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/parallel_download_job.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/parallel_download_job.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/parallel_download_job_unittest.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/browser/download/save_file.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/public/test/fake_download_item.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/public/test/fake_download_item.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/public/test/mock_download_item.h
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/content/public/test/test_file_error_injector.cc
[modify] https://crrev.com/4a8fc9da53e66db1c6aa7812114fb40812a93d49/tools/metrics/ukm/ukm.xml