Try to flush DOMStorage too when ending the browsing session.

chrome/browser/browser_process_impl.cc

Index: chrome/browser/browser_process_impl.cc
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 39dc70edf71dbc9bbb7802e5129715c43cb1c344..8c3272e24499a2587bc2ad66e12756d829ae1007 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -7,6 +7,7 @@
 #include <stddef.h>
 
 #include <algorithm>
+#include <iterator>
 #include <map>
 #include <utility>
 #include <vector>
@@ -398,6 +399,8 @@ void BrowserProcessImpl::PostDestroyThreads() {
 
 namespace {
 
+using TaskRunnerVector = std::vector<scoped_refptr<base::SequencedTaskRunner>>;
+
 // Used at the end of session to block the UI thread for completion of sentinel
 // tasks on the set of threads used to persist profile data and local state.
 // This is done to ensure that the data has been persisted to disk before
@@ -411,6 +414,10 @@ class RundownTaskCounter :
   // of times before calling TimedWait.
   void Post(base::SequencedTaskRunner* task_runner);
 
+  // Posts a rundown task to each runner in |runners|, where the rundown task
+  // for runner[n+1] is posted during rundown task execution for runner[n].
+  void PostSerially(TaskRunnerVector runners);
+
   // Waits until the count is zero or |end_time| is reached.
   // This can only be called once per instance. Returns true if a count of zero
   // is reached or false if the |end_time| is reached. It is valid to pass an
@@ -425,6 +432,9 @@ class RundownTaskCounter :
   // zero.
   void Decrement();
 
+  void RundownSerially(TaskRunnerVector::const_iterator it,
+                       TaskRunnerVector runner);
+
   // The count starts at one to defer the possibility of one->zero transitions
   // until TimedWait is called.
   base::AtomicRefCount count_;
@@ -451,6 +461,16 @@ void RundownTaskCounter::Post(base::SequencedTaskRunner* task_runner) {
       base::Bind(&RundownTaskCounter::Decrement, this));
 }
 
+void RundownTaskCounter::PostSerially(TaskRunnerVector runners) {
+  if (runners.empty())
+    return;
+  base::AtomicRefCountInc(&count_);
+  TaskRunnerVector::const_iterator it = runners.begin();
+  (*it)->PostNonNestableTask(
+      FROM_HERE, base::Bind(&RundownTaskCounter::RundownSerially, this, it + 1,
+                            base::Passed(&runners)));
+}
+
 void RundownTaskCounter::Decrement() {
   if (!base::AtomicRefCountDec(&count_))
     waitable_event_.Signal();
@@ -463,6 +483,17 @@ bool RundownTaskCounter::TimedWaitUntil(const base::TimeTicks& end_time) {
   return waitable_event_.TimedWaitUntil(end_time);
 }
 
+void RundownTaskCounter::RundownSerially(TaskRunnerVector::const_iterator it,
+                                         TaskRunnerVector runners) {
+  if (it == runners.end()) {
+    Decrement();
+    return;
+  }
+  (*it)->PostNonNestableTask(
+      FROM_HERE, base::Bind(&RundownTaskCounter::RundownSerially, this, it + 1,
+                            base::Passed(&runners)));
+}
+
 }  // namespace
 
 void BrowserProcessImpl::EndSession() {
@@ -473,8 +504,7 @@ void BrowserProcessImpl::EndSession() {
   const bool pref_service_enabled =
       base::FeatureList::IsEnabled(features::kPrefService);
   std::vector<scoped_refptr<base::SequencedTaskRunner>> profile_writer_runners;
-  for (size_t i = 0; i < profiles.size(); ++i) {
-    Profile* profile = profiles[i];
+  for (Profile* profile : profiles) {
     profile->SetExitType(Profile::EXIT_SESSION_ENDED);
     if (profile->GetPrefs()) {
       profile->GetPrefs()->CommitPendingWrite();
@@ -527,15 +557,31 @@ void BrowserProcessImpl::EndSession() {
   // processes to launch, this can result in a hang. See
   // http://crbug.com/318527.
   const base::TimeTicks end_time = base::TimeTicks::Now() + kEndSessionTimeout;
-  const bool timed_out = !rundown_counter->TimedWaitUntil(end_time);
-  if (timed_out || !pref_service_enabled)
+  if (!rundown_counter->TimedWaitUntil(end_time))
     return;
 
-  scoped_refptr<RundownTaskCounter> profile_write_rundown_counter(
+  if (pref_service_enabled) {
+    scoped_refptr<RundownTaskCounter> profile_write_rundown_counter(
+        new RundownTaskCounter());
+    for (auto& profile_writer_runner : profile_writer_runners)
+      profile_write_rundown_counter->Post(profile_writer_runner.get());
+    if (!profile_write_rundown_counter->TimedWaitUntil(end_time))
+      return;
+  }
+
+  // Time permitting, give other storage systems a chance to flush caches.
+  auto flush_function = [](scoped_refptr<RundownTaskCounter> rundown_counter,
+                           content::StoragePartition* partition) {
+    rundown_counter->PostSerially(partition->Flush());
+  };
+  scoped_refptr<RundownTaskCounter> flush_storage_rundown_counter(
       new RundownTaskCounter());
-  for (auto& profile_writer_runner : profile_writer_runners)
-    profile_write_rundown_counter->Post(profile_writer_runner.get());
-  profile_write_rundown_counter->TimedWaitUntil(end_time);
+  for (Profile* profile : profiles) {
+    content::BrowserContext::ForEachStoragePartition(
+        profile,
+        base::BindRepeating(flush_function, flush_storage_rundown_counter));
+  }
+  flush_storage_rundown_counter->TimedWaitUntil(end_time);
 #else
   NOTIMPLEMENTED();
 #endif