[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 db514fc79b10160fb30c390d5b3fb4f11b3a6154..17c7348475e5ec367953af20f3b9249c07bafc3f 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -11308,6 +11308,37 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Manifest" enum="Boolean">

[Mark P, 2014/10/03 19:57:49]

Can you move this histogram into a subgroup such as
"Manifest.PropertiesPresent".  It's confusing that have this group that has
suffixes and then you have other histograms that also come after this prefix.
 

[mlamouri (slow - plz ping), 2014/10/07 11:11:39]

Done.

+  <owner>mlamouri@chromium.org</owner>
+  <summary>
+    Tracks which properties of a Manifest were present when it was parsed. If a
+    property can't be parsed, it will be recorded as not present. These
+    histograms will only be used if the Manifest was correctly fetched and
+    parsed and the parsed manifest is not empty.
+  </summary>
+</histogram>
+
+<histogram name="Manifest.FetchResult" enum="ManifestFetchResultType">
+  <owner>mlamouri@chromium.org</owner>
+  <summary>
+    Tracks whether the Manifest fetch succeed and why it failed if it failed.
+  </summary>
+</histogram>
+
+<histogram name="Manifest.IsEmpty" enum="Boolean">
+  <owner>mlamouri@chromium.org</owner>
+  <summary>Tracks whether the parsed Manifest is the empty Manifest.</summary>
+</histogram>
+
+<histogram name="Manifest.ParseSuccess" enum="Boolean">
+  <owner>mlamouri@chromium.org</owner>
+  <summary>
+    Tracks the Manifest parsing result. A failure will be recorded if the
+    Manifest was incorrectly structured. This doesn't take into account parse
+    failures for each individual properties.
+  </summary>
+</histogram>
+
 <histogram name="Media.AcceleratedCompositingActive" enum="BooleanSuccess">
   <obsolete>
     Deprecated as of July 21, 2014.
@@ -45829,6 +45860,12 @@ To add a new entry, add it with any value and run test to compute valid value.
   </int>
 </enum>
 
+<enum name="ManifestFetchResultType" type="int">
+  <int value="0" label="Fetch succeeded"/>
+  <int value="1" label="Fetch failed because of empty URL"/>
+  <int value="2" label="Fetch failed (unspecified reason)"/>
+</enum>
+
 <enum name="MappedCSSProperties" type="int">
 <!-- Generated from ../../../third_party/WebKit/Source/core/frame/UseCounter.cpp -->
 
@@ -54170,6 +54207,17 @@ 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="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()."/>