Add UMA metrics for profile switching.

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 30eb8601fe704b80fd48da67f8d28d09fcd62d2a..77d6765955e89d37987ed40c71ed42500135e69c 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -27857,6 +27857,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Profile.NumberOfSwitches">
+  <owner>anthonyvd@chromium.org</owner>
+  <summary>
+    Counts the number of times profiles were switched in a browser session. This
+    value is incremented when a profile is switched to and the result is logged
+    during shutdown.
+  </summary>
+</histogram>
+
 <histogram name="Profile.NumberOfUnusedProfiles">
   <owner>mlerman@chromium.org</owner>
   <summary>
@@ -62089,6 +62098,19 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="Profile.DesktopMenu"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="ProfileOpenState" separator=".">
+  <suffix name="ToOpenedProfile"
+      label="The profile being switched to was already loaded and had at
+             least one open browser"/>
+  <suffix name="ToUnopenedProfile"
+      label="The profile being switched to had not yet been loaded this
+             Chrome session"/>
+  <suffix name="ToOpenedProfileWithoutBrowser"
+      label="The profile being switched to was already opened and had no
+             active browsers"/>
+  <affected-histogram name="Profile.OpenMethod"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="ProfilePictureDownload" separator=".">
   <suffix name="Default.OOBE" label="default picture, in OOBE"/>
   <suffix name="Default.LoggedIn" label="default picture, after login"/>