localStorage: Aggressively flush to disk for Android WebView.

Android WebView does not save data during shutdown like Chrome does.
Adding an --enable-aggressive-domstorage-flushing flag to return the
DOM Storage implementation to the prior implementation which had a 1
sec. timer to flush the commit queue.

BUG=479767

Review URL: https://codereview.chromium.org/1129233003

Cr-Commit-Position: refs/heads/master@{#329070}

2 files changed, 17 insertions, 0 deletions

diff --git a/content/browser/dom_storage/dom_storage_area.cc b/content/browser/dom_storage/dom_storage_area.cc
index 56a1fd0..67c7b98 100644
--- a/content/browser/dom_storage/dom_storage_area.cc
+++ b/content/browser/dom_storage/dom_storage_area.cc
@@ -42,6 +42,8 @@ const int kMaxCommitsPerHour = 6;
 
 }  // namespace
 
+bool DOMStorageArea::s_aggressive_flushing_enabled_ = false;
+
 DOMStorageArea::RateLimiter::RateLimiter(size_t desired_rate,
                                          base::TimeDelta time_quantum)
     : rate_(desired_rate), samples_(0), time_quantum_(time_quantum) {
@@ -90,6 +92,10 @@ GURL DOMStorageArea::OriginFromDatabaseFileName(const base::FilePath& name) {
   return storage::GetOriginFromIdentifier(origin_id);
 }
 
+void DOMStorageArea::EnableAggressiveCommitDelay() {
+  s_aggressive_flushing_enabled_ = true;
+}
+
 DOMStorageArea::DOMStorageArea(const GURL& origin,
                                const base::FilePath& directory,
                                DOMStorageTaskRunner* task_runner)
@@ -388,6 +394,9 @@ void DOMStorageArea::StartCommitTimer() {
 }
 
 base::TimeDelta DOMStorageArea::ComputeCommitDelay() const {
+  if (s_aggressive_flushing_enabled_)
+    return base::TimeDelta::FromSeconds(1);
+
   base::TimeDelta elapsed_time = base::TimeTicks::Now() - start_time_;
   base::TimeDelta delay = std::max(
       base::TimeDelta::FromSeconds(kCommitDefaultDelaySecs),
diff --git a/content/browser/dom_storage/dom_storage_area.h b/content/browser/dom_storage/dom_storage_area.h
index 3a4b166..dd0df52 100644
--- a/content/browser/dom_storage/dom_storage_area.h
+++ b/content/browser/dom_storage/dom_storage_area.h
@@ -35,6 +35,12 @@ class CONTENT_EXPORT DOMStorageArea
   static base::FilePath DatabaseFileNameFromOrigin(const GURL& origin);
   static GURL OriginFromDatabaseFileName(const base::FilePath& file_name);
 
+  // Commence aggressive flushing. This should be called early in the startup -
+  // before any localStorage writing. Currently scheduled writes will not be
+  // rescheduled and will be flushed at the scheduled time after which
+  // aggressive flushing will commence.
+  static void EnableAggressiveCommitDelay();
+
   // Local storage. Backed on disk if directory is nonempty.
   DOMStorageArea(const GURL& origin,
                  const base::FilePath& directory,
@@ -153,6 +159,8 @@ class CONTENT_EXPORT DOMStorageArea
 
   void ShutdownInCommitSequence();
 
+  static bool s_aggressive_flushing_enabled_;
+
   int64 namespace_id_;
   std::string persistent_namespace_id_;
   GURL origin_;