Add UMA for --app-shim-error.

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 cfa152a82e82c983a69e7ed2bff3375856d50506..43dcff9abd7b88c0813efa1dae7ca91f6da8bffb 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -476,6 +476,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Apps.AppShimError" enum="NetErrorPageEvents">
+  <owner>rdsmith@chromium.org</owner>

[tapted, 2014/06/26 06:47:05]

probably the wrong owner, and summary below :)

[jackhou1, 2014/06/27 04:55:57]

Done.

+  <owner>ellyjones@chromium.org</owner>
+  <summary>
+    Counts of various events that can occur on the network error page. See the
+    histogram for details.
+  </summary>
+</histogram>
+
 <histogram name="Ash.ActiveTouchPoints">
   <owner>kuscher@google.com</owner>
   <owner>rbyers@chromium.org</owner>
@@ -34220,6 +34229,13 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="4" label="PROMO_SEEN"/>
 </enum>
 
+<enum name="AppShimError" type="int">
+  <int value="0" label="BITNESS_SHIM_32_CHROME_64"/>

[tapted, 2014/06/26 06:47:05]

I think it's preferable to have descriptive names -- these are just for the uma
UI

[jackhou1, 2014/06/27 04:55:57]

Done.

+  <int value="1" label="BITNESS_SHIM_64_CHROME_32"/>
+  <int value="2" label="BITNESS_SHIM_32_CHROME_32"/>
+  <int value="3" label="BITNESS_SHIM_64_CHROME_64"/>
+</enum>
+
 <enum name="AppsPageDragSource" type="int">
   <int value="0" label="Same apps pane"/>
   <int value="1" label="Different apps pane"/>