[DOMStorage] Rate limiting writes to disk.

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 004792d95d5a77797e02d24b8f563e86c4ca6e01..29a80ed02a0b979e98f61beea11f584adddd6f5d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -5550,49 +5550,6 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="DOMStorage.clear" units="milliseconds">
-  <owner>michaeln@chromium.org</owner>
-  <summary>
-    Duration to execute localStorage.clear() or sessionStorage.clear().
-  </summary>
-</histogram>
-
-<histogram name="DOMStorage.getItem" units="milliseconds">
-  <owner>michaeln@chromium.org</owner>
-  <summary>
-    Duration to execute localStorage.getItem() or sessionStorage.getItem().
-  </summary>
-</histogram>
-
-<histogram name="DOMStorage.key" units="milliseconds">
-  <owner>michaeln@chromium.org</owner>
-  <summary>
-    Duration to execute localStorage.key() or sessionStorage.key().
-  </summary>
-</histogram>
-
-<histogram name="DOMStorage.length" units="milliseconds">
-  <owner>michaeln@chromium.org</owner>
-  <summary>
-    Duration to execute localStorage.length() or sessionStorage.length().
-  </summary>
-</histogram>
-
-<histogram name="DOMStorage.removeItem" units="milliseconds">
-  <owner>michaeln@chromium.org</owner>
-  <summary>
-    Duration to execute localStorage.removeItem() or
-    sessionStorage.removeItem().
-  </summary>
-</histogram>
-
-<histogram name="DOMStorage.setItem" units="milliseconds">
-  <owner>michaeln@chromium.org</owner>
-  <summary>
-    Duration to execute localStorage.setItem() or sessionStorage.setItem().
-  </summary>
-</histogram>
-
 <histogram name="Download.AcceptRangesBytes.KBytes" units="KB">
   <owner>asanka@chromium.org</owner>
   <summary>The length of downloads for serves that accept byte ranges.</summary>
@@ -12228,6 +12185,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="LocalStorage.CommitDelay">
+  <owner>michaeln@chromium.org</owner>
+  <summary>
+    Delay between a page making changes and those changes being written to the
+    DB.
+  </summary>
+</histogram>
+
 <histogram name="LocalStorage.RendererLocalStorageSizeInKB" units="KB">
   <owner>michaeln@chromium.org</owner>
   <summary>