[ImportantSites] Adding usage metrics.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index c93a3e4fde61ad846cfec8685dcc8094dd64d4bc..43790bf77c55a0af44f2681b920b3cec353d227a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -369,6 +369,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Android.ManageSpace.ActionTaken"
+    enum="AndroidManageSpaceButton">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when the user presses a button in the 'Manage Space' screen for
+    Chrome. Note: the 'Clear App Data' option is likely incorrect, as the result
+    of that button disables UMA recording (as we factory reset the app).
+  </summary>
+</histogram>
+
 <histogram name="Android.ModerateBindingCount" units="bindings">
   <owner>jaekyun@chromium.org</owner>
   <summary>
@@ -17559,6 +17569,44 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="History.ClearBrowsingData.ImportantDeselectedNum">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when the user presses the 'clear' button when presented with the
+    list of important sites they might want to exclude from clearing browsing
+    data. We record the number of sites the user deselected, or protected, from
+    clearing. The default has all sites selected.
+  </summary>
+</histogram>
+
+<histogram name="History.ClearBrowsingData.ImportantDeselectedPercent">

[Mark P, 2016/06/30 05:29:09]

units="%"?

[dmurph, 2016/06/30 20:16:29]

Ah, right, thanks.

+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when the user presses the 'clear' button when presented with the
+    list of important sites they might want to exclude from clearing browsing
+    data. We record the percent of sites the user deselected, or protected, from
+    clearing. The default has all sites selected, which is 0%.
+  </summary>
+</histogram>
+
+<histogram name="History.ClearBrowsingData.ImportantDialogShown"
+    enum="BooleanShown">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when the user presses the 'clear' button in the clear browsing
+    dialog. We record 'true' when the important sites dialog is shown.

[Mark P, 2016/06/30 05:29:09]

when -> if
?

(i.e., the clear browsing dialog might not have an important site dialog within
it.  Is that true?)

[dmurph, 2016/06/30 20:16:29]

That sounds better, thanks.

+  </summary>
+</histogram>
+
+<histogram name="History.ClearBrowsingData.NumImportant">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when we successfuly fetched important sites in the clear browsing
+    data screen. This is the number of sites that we think are important to the
+    user.
+  </summary>
+</histogram>
+
 <histogram
     name="History.ClearBrowsingData.PasswordsDeletion.AdditionalDatatypesCount">
   <owner>msramek@chromium.org</owner>
@@ -64897,6 +64945,12 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="262154" label="4.10"/>
 </enum>
 
+<enum name="AndroidManageSpaceButton" type="int">
+  <int value="0" label="Clear Unimportant Storage"/>
+  <int value="1" label="Manage Site Storage"/>
+  <int value="2" label="Clear App Data"/>
+</enum>
+
 <enum name="AndroidMemoryNotificationBackground" type="int">
   <int value="0" label="TrimMemoryUiHidden"/>
   <int value="1" label="TrimMemoryBackground"/>