The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3f921557c4cb83453bfce0fe8637e489a90064ad

commit 3f921557c4cb83453bfce0fe8637e489a90064ad
Author: Luna Lu <loonybear@chromium.org>
Date: Wed Dec 13 22:00:36 2017

Drop UseCounter usage measurement on view-source pages.

For NTP, in UseCounter::DidCommitLoad, set the context to be disabled. Previously we skip
UseCounter::DidCommitLoad when it is a NTP. But this didn't prevent other features on the
NTP to be measured, which is incorrect.

Currently refreshing a view-source page will cause feature usage go up, which is
not ideal. Blink is using the original page's scheme instead of view-source
scheme. Dropping view-source activities would match page load metrics' policy.

UseCounter features below are being removed. They were added in
https://chromium.googlesource.com/chromium/src/+/6a361fd629fd216c5cb0a1108228a1d10585a136
  kImageDocument = 1274,
  kImageDocumentInFrame = 1310,
  kMediaDocument = 1311,
  kMediaDocumentInFrame = 1312,
  kPluginDocument = 1313,
  kPluginDocumentInFrame = 1314,
  kSinkDocument = 1315,
  kSinkDocumentInFrame = 1316,
  kTextDocument = 1317,
  kTextDocumentInFrame = 1318,
  kViewSourceDocument = 1319,
foolip@ added these features to figure out if it'd be safe to change what happens with
<iframe src="same-origin-video.webm">, since the DOM inside the iframe could be observed.
foolip@ confirmed that these features can be removed now.

Bug:  760114 
Change-Id: I3c07288e4cdd52f2da09cc89d343d4737aef41b1
Reviewed-on: https://chromium-review.googlesource.com/792171
Commit-Queue: Luna Lu <loonybear@chromium.org>
Reviewed-by: Rick Byers <rbyers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523897}
[delete] https://crrev.com/af93a1eedbc47abde6900376bdfa1d3ed1dd8f3f/third_party/WebKit/LayoutTests/images/image-use-counters.html
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/dom/SinkDocument.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/frame/LocalFrame.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/frame/UseCounter.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/frame/UseCounter.h
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/frame/UseCounterTest.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/html/HTMLViewSourceDocument.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/html/ImageDocument.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/html/PluginDocument.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/html/TextDocument.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/html/media/MediaDocument.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/Source/core/page/Page.cpp
[modify] https://crrev.com/3f921557c4cb83453bfce0fe8637e489a90064ad/third_party/WebKit/public/platform/web_feature.mojom

I would like to see this in 64 so that I will be able to collect data for usecounter 

The bug is marked as P3 or Feature. It should not be merged as M64 is in beta. 
Please contact the approriate milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), kbleicher@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot