Fix the DomStorage is "wicked slow" bug by adding a renderer side cache and using a predominantly async IPC message protocol.

- use DomStorageCachedArea + DomStorageProxy
- an ipc message throttling mechanism to defend against misbehaving usage
- less chatty storage event propagation
- diable sudden termination when domstorage messages are pending to allow changes to be flushed thru to the backend on page unload
- deleted the obsolete sync message types and handlers

BUG=94382,128482
Review URL: https://chromiumcodereview.appspot.com/10383123

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@139602 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 11 insertions, 4 deletions

diff --git a/webkit/dom_storage/dom_storage_area.cc b/webkit/dom_storage/dom_storage_area.cc
index 43f22f1..ab4d5f8 100644
--- a/webkit/dom_storage/dom_storage_area.cc
+++ b/webkit/dom_storage/dom_storage_area.cc
@@ -58,7 +58,7 @@ DomStorageArea::DomStorageArea(
     : namespace_id_(namespace_id), origin_(origin),
       directory_(directory),
       task_runner_(task_runner),
-      map_(new DomStorageMap(kPerAreaQuota)),
+      map_(new DomStorageMap(kPerAreaQuota + kPerAreaOverQuotaAllowance)),
       is_initial_import_done_(true),
       is_shutdown_(false),
       commit_batches_in_flight_(0) {
@@ -137,7 +137,7 @@ bool DomStorageArea::Clear() {
   if (map_->Length() == 0)
     return false;
 
-  map_ = new DomStorageMap(kPerAreaQuota);
+  map_ = new DomStorageMap(kPerAreaQuota + kPerAreaOverQuotaAllowance);
 
   if (backing_.get()) {
     CommitBatch* commit_batch = CreateCommitBatchIfNeeded();
@@ -176,7 +176,7 @@ void DomStorageArea::DeleteOrigin() {
     Clear();
     return;
   }
-  map_ = new DomStorageMap(kPerAreaQuota);
+  map_ = new DomStorageMap(kPerAreaQuota + kPerAreaOverQuotaAllowance);
   if (backing_.get()) {
     is_initial_import_done_ = false;
     backing_.reset(new DomStorageDatabase(backing_->file_path()));
@@ -195,7 +195,7 @@ void DomStorageArea::PurgeMemory() {
 
   // Drop the in memory cache, we'll reload when needed.
   is_initial_import_done_ = false;
-  map_ = new DomStorageMap(kPerAreaQuota);
+  map_ = new DomStorageMap(kPerAreaQuota + kPerAreaOverQuotaAllowance);
 
   // Recreate the database object, this frees up the open sqlite connection
   // and its page cache.
diff --git a/webkit/dom_storage/dom_storage_types.h b/webkit/dom_storage/dom_storage_types.h
index d2b65bf..155b9f4 100644
--- a/webkit/dom_storage/dom_storage_types.h
+++ b/webkit/dom_storage/dom_storage_types.h
@@ -15,8 +15,15 @@
 namespace dom_storage {
 
 // The quota for each storage area. Suggested by the spec.
+// This value is enforced in renderer processes.
 const size_t kPerAreaQuota = 5 * 1024 * 1024;
 
+// In the browser process we allow some overage to
+// accomodate concurrent writes from different renderers
+// that were allowed because the limit imposed in the renderer
+// wasn't exceeded.
+const size_t kPerAreaOverQuotaAllowance = 100 * 1024;
+
 // Value to indicate the localstorage namespace vs non-zero
 // values for sessionstorage namespaces.
 const int64 kLocalStorageNamespaceId = 0;