The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/642318401fc47bea352b860ab8786854abb7c314

commit 642318401fc47bea352b860ab8786854abb7c314
Author: aelias <aelias@chromium.org>
Date: Tue Mar 28 04:41:04 2017

Add a UMA counter for tap disambiguation result.

This is to collect data informing a possible removal of this feature.
In particular, only if the user tapped inside the popup can it be
considered to be a (possibly) successful UX; if the user dismissed it by
tapping outside or pressing the back button, then it can be considered
to have caused more harm than good.

BUG= 705117 

Review-Url: https://codereview.chromium.org/2775013002
Cr-Commit-Position: refs/heads/master@{#460013}

[modify] https://crrev.com/642318401fc47bea352b860ab8786854abb7c314/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
[modify] https://crrev.com/642318401fc47bea352b860ab8786854abb7c314/content/public/android/java/src/org/chromium/content/browser/PopupZoomer.java
[modify] https://crrev.com/642318401fc47bea352b860ab8786854abb7c314/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1b55156e5277d39580f4063af924ec7347375ebc

commit 1b55156e5277d39580f4063af924ec7347375ebc
Author: aelias <aelias@chromium.org>
Date: Sat Apr 01 00:46:05 2017

Refine tap disambiguation UMA to track same-node/different-node.

The Android tap disambiguation feature makes users retap on a zoomed screenshot
when the user tapped on tiny close-together links.  This feature is
currently being considered for removal.  If the user's tap would've been
anyway, in the first place, accurately resolved to the node they
ultimately selected after disambiguation, then the popup UI achieved
nothing and we should consider this a failure case.

Notes:
- Because this must be measured in the renderer and the synthetic
taps sent before had nothing to identify them as relating to
disambiguation, I introduced a new ViewMsg_ResolveTapDisambiguation.
I think this is anyway a better architecture -- this is a highly unusual
scenario not much resembling an ordinary touch gesture, and risks
interacting weirdly with ordinary event routing.
- Although handling this in WebViewImpl is broken with OOPIF, this feature
is already broken with OOPIF.  That's one of the reasons it's considered
for removal.
- I'm using hit node top-left offset relative the document as an
identifier the DOM node itself.  This seems less sketchy than persisting
a pointer, and it's good enough for this use case because the page is
generally static during a tap disambiguation (if it self-scrolls, for
instance, the popup will be dismissed with category OTHER).

BUG= 705117 

Review-Url: https://codereview.chromium.org/2783233004
Cr-Commit-Position: refs/heads/master@{#461290}

[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/browser/android/content_view_core_impl.cc
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/browser/android/content_view_core_impl.h
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/browser/renderer_host/render_widget_host_view_android.cc
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/browser/renderer_host/render_widget_host_view_android.h
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/common/view_messages.h
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/public/android/java/src/org/chromium/content/browser/PopupZoomer.java
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/renderer/render_view_impl.cc
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/content/renderer/render_view_impl.h
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/third_party/WebKit/Source/web/WebViewImpl.cpp
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/third_party/WebKit/Source/web/WebViewImpl.h
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/third_party/WebKit/public/web/WebView.h
[modify] https://crrev.com/1b55156e5277d39580f4063af924ec7347375ebc/tools/metrics/histograms/histograms.xml