Bug 1309256 - Add documentation for BrowserUsageTelemetry. r=gfritzsche

MozReview-Commit-ID: GVclrfo5Zhl

--HG--
extra : rebase_source : 7294f0409d11207bd3af4e624023180fec23589a

browser/docs/BrowserUsageTelemetry.rst

@@ -0,0 +1,28 @@
+.. _browserusagetelemetry:
+
+=======================
+Browser Usage Telemetry
+=======================
+
+The `BrowserUsageTelemetry.jsm <https://dxr.mozilla.org/mozilla-central/source/browser/modules/BrowserUsageTelemetry.jsm>`_ module is the main module for measurements regarding the browser usage (e.g. tab and window counts, search counts, ...).
+
+The measurements recording begins right after the ``SessionStore`` has finished restoring the session (i.e. restoring tabs/windows after Firefox starts).
+
+Search telemetry
+================
+This module exposes the ``recordSearch`` method, which serves as the main entry point for recording search related Telemetry. It records only the search *counts* per engine and the origin of the search, but nothing pertaining the search contents themselves.
+
+As the transition to the ``BrowserUsageTelemetry`` happens, the ``recordSearch`` calls are dispatched through `BrowserSearch.recordSearchInTelemetry <https://dxr.mozilla.org/mozilla-central/rev/3e73fd638e687a4d7f46613586e5156b8e2af846/browser/base/content/browser.js#3752>`_, that is called by all the search related UI components (urlbar, searchbar, context menu and about\:\* pages).
+
+A list of the components recording search Telemetry can be found using the following `DXR search <https://dxr.mozilla.org/mozilla-central/search?q=recordSearchInTelemetry>`_.
+
+Measured interactions
+=====================
+The usage telemetry module currently measures these interactions with the browser:
+
+- *tab and window engagement*: counts the number of non-private tabs and windows opened in a subsession, after the session is restored (see e.g. ``browser.engagement.max_concurrent_tab_count``);
+- *URI loads*: counts the number of page loads (doesn't track and send the addresses, just the counts) directly triggered by the users (see ``browser.engagement.total_uri_count``);
+- *navigation events*: at this time, this only counts the number of time a page load is triggered by a particular UI interaction (e.g. by searching through the URL bar, see ``browser.engagement.navigation.urlbar``).
+
+
+Please see `Scalars.yaml <https://dxr.mozilla.org/mozilla-central/source/toolkit/components/telemetry/Scalars.yaml>`_ for the full list of tracked interactions.

browser/docs/index.rst

@@ -9,3 +9,4 @@ This is the nascent documentation of the Firefox front-end code.
 
    DirectoryLinksProvider
    UITelemetry
+   BrowserUsageTelemetry

toolkit/components/telemetry/docs/collection/index.rst

@@ -29,3 +29,7 @@ The current data collection possibilities include:
    histograms
    measuring-time
    custom-pings
+
+Browser Usage Telemetry
+~~~~~~~~~~~~~~~~~~~~~~~
+For more information, see :ref:`browserusagetelemetry`.