[BlobStorage] Enabling disk paging and direct storage.

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 c32738ed925dc06bb79ce45ead7f9600071d7a4c..76db7ed40ed3d8b44ec4c108f3b694b260f86712 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -63906,6 +63906,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Storage.Blob.CleanupSuccess" enum="Boolean">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when the old blob storage directories are cleared. This occurs on
+    storage partition initialization, and is not recorded if there are no
+    directories to clear. The value indicates if the file operations were a
+    success.
+  </summary>
+</histogram>
+
 <histogram name="Storage.Blob.CreateDirectoryResult" enum="PlatformFileError">
   <owner>dmurph@chromium.org</owner>
   <summary>
@@ -63956,6 +63966,24 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Storage.Blob.MaxDiskSpace" units="MB">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Records the calculated max disk space the blob storage system can use.
+    Recorded on storage partition initialization.
+  </summary>
+</histogram>
+
+<histogram name="Storage.Blob.MaxDiskSpaceAdjustment"
+    enum="BlobStorageDiskSpaceAdjustment">
+  <owner>dmurph@chromium.org</owner>
+  <summary>
+    Recorded when the blob system adjusts its maximum disk space. This can
+    happen after any file operations in the blob system (paging data to disk or
+    saving a new blob directly to disk).
+  </summary>
+</histogram>
+
 <histogram name="Storage.Blob.PageFileSize" units="KB">
   <owner>dmurph@chromium.org</owner>
   <summary>
@@ -77215,6 +77243,23 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="5" label="Referenced blob broken"/>
 </enum>
 
+<enum name="BlobStorageDiskSpaceAdjustment" type="int">
+  <summary>
+    When the blob storage system adjusts its max disk space, it can do so for
+    these reasons.
+  </summary>
+  <int value="0"
+      label="Disk usage frozen because minimum disk availability was reached."/>
+  <int value="1"
+      label="Max disk usage reduced because disk space is approaching minimum
+             disk availability"/>
+  <int value="2"
+      label="Max disk usage increased because disk space has increased, but
+             minimum disk availability is still close."/>
+  <int value="3"
+      label="Max disk usage restored to desired limit after being adjusted."/>
+</enum>
+
 <enum name="BluetoothAvailability" type="int">
   <int value="0" label="Unexpected error"/>
   <int value="1" label="Not available"/>