Measure time spent in SharedPrefs-loading StrictMode violations.

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 fa97f26772690767a820b9a0471d6eea6599bebe..4e4ffdabffc2dfc70a854d02e859f80c83c41e0e 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -312,6 +312,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Android.StrictMode.DocumentModeSharedPrefs" units="ms">
+  <owner>hartmanng@chromium.org</owner>
+  <owner>yfriedman@chromium.org</owner>
+  <summary>
+    Measures the amount of time due to a StrictMode violation from fetching the
+    DocumentMode shared preferences file.
+  </summary>
+</histogram>
+
 <histogram name="Android.StrictMode.DocumentTabStateLoad" units="ms">
   <owner>wnwen@chromium.org</owner>
   <owner>yfriedman@chromium.org</owner>
@@ -384,6 +393,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Android.StrictMode.WebappSharedPrefs" units="ms">
+  <owner>hartmanng@chromium.org</owner>
+  <owner>yfriedman@chromium.org</owner>
+  <summary>
+    Measures the amount of time due to a StrictMode violation from fetching the
+    Webapp shared preferences file.
+  </summary>
+</histogram>
+
 <histogram name="AndroidTabCloseUndo.Toast"
     enum="AndroidTabCloseUndoToastEvent">
   <owner>dtrainor@chromium.org</owner>