Add UMA metrics for desktop memory pressure notifications.

content/browser/dom_storage/dom_storage_area.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/dom_storage/dom_storage_area.h"
 
 #include <inttypes.h>
 
 #include <algorithm>
 #include <cctype>  // for std::isalnum
@@ skipping 289 matching lines @@
   map_ = new DOMStorageMap(kPerStorageAreaQuota +
                            kPerStorageAreaOverQuotaAllowance);
   if (backing_) {
     is_initial_import_done_ = false;
     backing_->Reset();
     backing_->DeleteFiles();
   }
 }
 
 void DOMStorageArea::PurgeMemory() {
+/*
   DCHECK(!is_shutdown_);
   // Purging sessionStorage is not supported; it won't work with FastClear.
   DCHECK(!session_storage_backing_.get());
   if (!is_initial_import_done_ ||  // We're not using any memory.
       !backing_.get() ||  // We can't purge anything.
       HasUncommittedChanges())  // We leave things alone with changes pending.
     return;
 
   // Drop the in memory cache, we'll reload when needed.
   is_initial_import_done_ = false;
   map_ = new DOMStorageMap(kPerStorageAreaQuota +
                            kPerStorageAreaOverQuotaAllowance);
 
   // Recreate the database object, this frees up the open sqlite connection
   // and its page cache.
   backing_->Reset();
+  */
 }
 
 void DOMStorageArea::Shutdown() {
   if (is_shutdown_)
     return;
   is_shutdown_ = true;
 
   if (commit_batch_) {
     DCHECK(backing_);
     PopulateCommitBatchValues();
@@ skipping 207 matching lines @@
         commit_batch_->clear_all_first,
         commit_batch_->changed_values);
     DCHECK(success);
   }
   commit_batch_.reset();
   backing_.reset();
   session_storage_backing_ = NULL;
 }
 
 }  // namespace content