guidou@ Now that enumerateDevices resides in blink, I think we cannot use the call UpdateWebRTCMethodCount(WEBKIT_GET_MEDIA_DEVICES); So, should we now use https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/Histogram.h?l=21? Your suggestion in taking this forward, please?

I think the most straightforward way to proceed is to make a wrapper of UpdateWebRTCMethodCount available in blink::Platform.
We also need to move the JavaScriptApiName enum to WebKit/public (preferably renamed to WebRtcApiName.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d

commit 42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d
Author: Chandan Padhi <c.padhi@samsung.com>
Date: Fri Mar 16 20:27:53 2018

Restore UMA histograms for MediaDevices.enumerateDevices()

This CL also makes the WebRTC UMA utility available in Blink for
features that have been migrated from content/renderer.

UMA histograms for MediaDevices.enumerateDevices() got removed while
migrating it from content to blink in https://crrev.com/c/808128.
This CL restores the same.


Bug:  821331 
Change-Id: Iaba8ede9cfe36dfde0f6d18203f09be42bd15061
Reviewed-on: https://chromium-review.googlesource.com/961778
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Commit-Queue: Chandan Padhi <c.padhi@samsung.com>
Cr-Commit-Position: refs/heads/master@{#543806}
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media/stream/user_media_client_impl.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media/webrtc/peer_connection_dependency_factory.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media/webrtc/webrtc_uma_histograms.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media/webrtc/webrtc_uma_histograms.h
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media/webrtc/webrtc_uma_histograms_unittest.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media_capture_from_element/canvas_capture_handler.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media_capture_from_element/html_video_element_capturer_source.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/media_recorder/media_recorder_handler.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/renderer_blink_platform_impl.cc
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/content/renderer/renderer_blink_platform_impl.h
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/third_party/WebKit/Source/modules/mediastream/MediaDevices.cpp
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/third_party/WebKit/public/BUILD.gn
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/third_party/WebKit/public/platform/Platform.h
[add] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/third_party/WebKit/public/platform/WebRTCAPIName.h
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/42a1626c91d3c1263c1ff7bf7fa7cac80c25ef7d/tools/metrics/histograms/histograms.xml