[DOMStorage] Rate limiting writes to disk.

content/browser/dom_storage/dom_storage_namespace.cc

Index: content/browser/dom_storage/dom_storage_namespace.cc
diff --git a/content/browser/dom_storage/dom_storage_namespace.cc b/content/browser/dom_storage/dom_storage_namespace.cc
index 75bfdaacb71bcee82a6a52b89f0940a58c207198..fc85d83396a319177252cdeee6ae46e3054cfb0b 100644
--- a/content/browser/dom_storage/dom_storage_namespace.cc
+++ b/content/browser/dom_storage/dom_storage_namespace.cc
@@ -123,16 +123,23 @@ void DOMStorageNamespace::PurgeMemory(PurgeOption option) {
     return;  // We can't purge w/o backing on disk.
   AreaMap::iterator it = areas_.begin();
   while (it != areas_.end()) {
-    // Leave it alone if changes are pending
-    if (it->second.area_->HasUncommittedChanges()) {
+    const AreaHolder& holder = it->second;
+
+    // We can't purge if there are changes pending.
+    if (holder.area_->HasUncommittedChanges()) {
+      if (holder.open_count_ == 0) {
+         // Schedule an immediate commit so the next time we're asked to purge,
+         // we can drop it from memory.
+         holder.area_->ScheduleImmediateCommit();
+      }
       ++it;
       continue;
     }
 
     // If not in use, we can shut it down and remove
     // it from our collection entirely.
-    if (it->second.open_count_ == 0) {
-      it->second.area_->Shutdown();
+    if (holder.open_count_ == 0) {
+      holder.area_->Shutdown();
       areas_.erase(it++);
       continue;
     }
@@ -140,7 +147,7 @@ void DOMStorageNamespace::PurgeMemory(PurgeOption option) {
     if (option == PURGE_AGGRESSIVE) {
       // If aggressive is true, we clear caches and such
       // for opened areas.
-      it->second.area_->PurgeMemory();
+      holder.area_->PurgeMemory();
     }
 
     ++it;