Add bad block count histograms

This corresponds to the Chromecast change at this URL:
https://eureka-internal-review.googlesource.com/#/c/19857/

R=gwendal@chromium.org, isherman@chromium.org, robertshield@chromium.org, semenzato@chromium.org, asvitkine@chromium.org
BUG=384533

Review URL: https://codereview.chromium.org/335913002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278002 0039d316-1c4b-4281-b951-d872f2087c98

tools/metrics/histograms/histograms.xml

@@ -19395,6 +19395,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <summary>Chrome OS stateful partition usage level.</summary>
 </histogram>
 
+<histogram name="Platform.Storage.Flash.BadBlocks">
+  <owner>dehrenberg@chromium.org</owner>
+  <summary>
+    The number of blocks marked bad in an MTD partition. This is relevant for
+    devices with raw NAND flash, such as Chromecast. Sampled once daily, if the
+    Chromecast is on for any significant length of time in the day.
+  </summary>
+</histogram>
+
 <histogram name="Platform.SwapInLong" units="pages/second">
   <owner>sonnyrao@chromium.org</owner>
   <summary>
@@ -45802,6 +45811,27 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <affected-histogram name="Autofill.Quality.ServerType.ByFieldType"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="BadBlockCounts" separator=".">
+  <suffix name="Backupsys" label="backupsys partition"/>
+  <suffix name="Bbt" label="bbt partition"/>
+  <suffix name="Block0" label="block0 partition"/>
+  <suffix name="Bootloader" label="bootloader partition"/>
+  <suffix name="Cache" label="cache partition"/>
+  <suffix name="Factory_store" label="factory_store partition"/>
+  <suffix name="Fts" label="fts partition"/>
+  <suffix name="Kernel" label="kernel partition"/>
+  <suffix name="Postbootloader" label="postbootloader partition"/>
+  <suffix name="Postbootloader-B" label="postbootloader-B partition"/>
+  <suffix name="Prebootloader" label="prebootloader partition"/>
+  <suffix name="Recovery" label="recovery partition"/>
+  <suffix name="Rootfs" label="rootfs partition"/>
+  <suffix name="Total" label="total partition"/>
+  <suffix name="TZ" label="TZ partition"/>
+  <suffix name="TZ-B" label="TZ-B partition"/>
+  <suffix name="Userdata" label="userdata partition"/>
+  <affected-histogram name="Platform.Storage.Flash.BadBlocks"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="CacheListSize">
   <suffix name="CacheListSize_12" label="Control"/>
   <suffix name="CacheListSize_13" label="Extended deleted list (2x)"/>