[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 291b5c1b79721542980849322e2bbe54d4cebe3d..82de50a431ae4cc9996223c3ccd34535e3eea962 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -64296,6 +64296,16 @@ 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>
@@ -64346,6 +64356,26 @@ 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 changes adjustment types on its disk size. The
+    disk can either be Frozen, Adjusted (near min external available disk
+    space), or Normal. We record when we transition between these states, which
+    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>
@@ -77700,6 +77730,25 @@ 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 be frozen,
+    adjusted (near min external disk availability), or normal. These values
+    record the transitions between those states.
+  </summary>
+  <int value="0"
+      label="Disk usage frozen because minimum disk availability was reached."/>
+  <int value="1"
+      label="Max disk usage reduced from a normal state because disk space is
+             approaching minimum disk availability."/>
+  <int value="2"
+      label="Max disk usage increased from a frozen state to adjusted, as
+             minimum external disk availability is still close."/>
+  <int value="3"
+      label="Max disk usage restored to desired limit after being adjusted or
+             frozen."/>
+</enum>
+
 <enum name="BluetoothAvailability" type="int">
   <int value="0" label="Unexpected error"/>
   <int value="1" label="Not available"/>