Remove logic for unused foreground auto-launch mode on Windows.

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 76f0de6f982464c072325371593ec30590f2bb4e..adbbdc3e615b5caa13eeb93824452ec3b14e75f6 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2639,11 +2639,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="BackgroundMode.OnStartup.AutoLaunchState"
-    enum="AutoLaunchState">
+    enum="BooleanBackgroundMode">

[gab, 2015/11/11 21:04:15]

@rkaplow: Is this sane? Essentially we're going from an enum (0-3) to a 0-1
(i.e., a bool) where 0/1 still mean the same thing they used to but 2/3 are no
more. Can we thus re-use the same histogram? That would make for a better
continuity in the data if so (note, report levels for 2/3 were SO low (< 0.00%)
that it shouldn't affect bucket counts for 0/1 when comparing before/after).

[rkaplow, 2015/11/12 18:00:26]

We generally don't really like having data coming in untracked - we would prefer
if you left the enum, and changed the labels to DEPRECATED_*.
I realize it's unfortunate that our dashboards will still show the old values
(in dropdowns, etc.). I think that's a bug in the frontends I can report
separately.

[gab, 2015/11/12 18:44:26]

Ok, brought back the enum in histograms.xml. Can I still only use
UMA_HISTOGRAM_BOOLEAN in the code (it's a 0/1 enum in practice IIRC, right?).

   <owner>gab@chromium.org</owner>
   <summary>
-    Logged during BackgroundModeManager's initialization. Indicates the
-    AutoLaunchState the current browser process was launched in.
+    Logged during BackgroundModeManager's initialization. Indicates whether the
+    browser process was launched in background mode or not.
   </summary>
 </histogram>
 
@@ -54131,13 +54131,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="11" label="User edited autofilled field (once)"/>
 </enum>
 
-<enum name="AutoLaunchState" type="int">
-  <int value="0" label="AUTO_LAUNCH_NONE"/>
-  <int value="1" label="AUTO_LAUNCH_BACKGROUND"/>
-  <int value="2" label="AUTO_LAUNCH_FOREGROUND"/>
-  <int value="3" label="AUTO_LAUNCH_FOREGROUND_USELESS"/>
-</enum>
-
 <enum name="BackgroundModeMenuItem" type="int">
   <int value="0" label="About"/>
   <int value="1" label="Task manager"/>
@@ -54498,6 +54491,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Available"/>
 </enum>
 
+<enum name="BooleanBackgroundMode" type="int">
+  <int value="0" label="Normal launch"/>
+  <int value="1" label="Launch in background mode"/>
+</enum>
+
 <enum name="BooleanBlocked" type="int">
   <int value="0" label="Not Blocked"/>
   <int value="1" label="Blocked"/>