[Manifest] Add metrics recording.

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 9d91abe1f86490ecb7089a16e1fe3031f57edefd..4e2c7cf763a225b842f842bae6c18233a2312ebe 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -11308,6 +11308,20 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Manifest" enum="Boolean">
+  <owner>mlamouri@chromium.org</owner>
+  <summary>
+    Tracks which properties of a Manifest were present when it was parsed. This
+    also recording whether the Manifest was empty which can happen when the
+    parsing failed.
+  </summary>
+</histogram>
+
+<histogram name="Manifest.FetchSuccess" enum="Boolean">
+  <owner>mlamouri@chromium.org</owner>
+  <summary>Tracks whether a Manifest fetch was successful.</summary>
+</histogram>
+
 <histogram name="Media.AcceleratedCompositingActive" enum="BooleanSuccess">
   <obsolete>
     Deprecated as of July 21, 2014.
@@ -54171,6 +54185,18 @@ To add a new entry, add it with any value and run test to compute valid value.
   <affected-histogram name="LocalStorage.RendererTimeToPrimeLocalStorage"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="ManifestProperties" separator=".">
+  <suffix name="IsEmpty"/>
+  <suffix name="name"/>
+  <suffix name="short_name"/>
+  <suffix name="start_url"/>
+  <suffix name="display"/>
+  <suffix name="orientation"/>
+  <suffix name="icons"/>
+  <suffix name="gcm_sender_id"/>
+  <affected-histogram name="Manifest"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="MediaAudioInputControllerTime" separator=".">
   <suffix name="CloseTime" label="Measures the time taken for DoClose()."/>
   <suffix name="CreateTime" label="Measures the time taken for DoCreate()."/>