Derive DomStorageTaskRunner from base::TaskRunner now that it exists.

BUG=106763
Review URL: https://chromiumcodereview.appspot.com/9689033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@126500 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 47 insertions, 33 deletions

diff --git a/webkit/dom_storage/dom_storage_task_runner.cc b/webkit/dom_storage/dom_storage_task_runner.cc
index 3ea1b3a..050cf16 100644
--- a/webkit/dom_storage/dom_storage_task_runner.cc
+++ b/webkit/dom_storage/dom_storage_task_runner.cc
@@ -21,47 +21,53 @@ DomStorageTaskRunner::DomStorageTaskRunner(
 DomStorageTaskRunner::~DomStorageTaskRunner() {
 }
 
-bool DomStorageTaskRunner::PostTask(
+bool DomStorageTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
-    const base::Closure& task) {
-  return message_loop_->PostTask(from_here, task);
+    const base::Closure& task,
+    base::TimeDelta delay) {
+  return message_loop_->PostDelayedTask(from_here, task, delay);
 }
 
 bool DomStorageTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
-    base::TimeDelta delay) {
-  return message_loop_->PostDelayedTask(from_here, task, delay);
+    int64 delay_ms) {
+  return PostDelayedTask(
+      from_here, task, base::TimeDelta::FromMilliseconds(delay_ms));
+}
+
+bool DomStorageTaskRunner::RunsTasksOnCurrentThread() const {
+  return true;
 }
 
 // DomStorageWorkerPoolTaskRunner
 
 DomStorageWorkerPoolTaskRunner::DomStorageWorkerPoolTaskRunner(
     base::SequencedWorkerPool* sequenced_worker_pool,
+    base::SequencedWorkerPool::SequenceToken sequence_token,
     base::MessageLoopProxy* delayed_task_loop)
     : DomStorageTaskRunner(delayed_task_loop),
       sequenced_worker_pool_(sequenced_worker_pool),
-      sequence_token_(
-          sequenced_worker_pool->GetNamedSequenceToken("dom_storage_token")) {
+      sequence_token_(sequence_token) {
 }
 
 DomStorageWorkerPoolTaskRunner::~DomStorageWorkerPoolTaskRunner() {
 }
 
-bool DomStorageWorkerPoolTaskRunner::PostTask(
-    const tracked_objects::Location& from_here,
-    const base::Closure& task) {
-  // We can skip on shutdown as the destructor of DomStorageArea will ensure
-  // that any remaining data is committed to disk.
-  return sequenced_worker_pool_->PostSequencedWorkerTaskWithShutdownBehavior(
-      sequence_token_, from_here, task,
-      base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
-}
-
 bool DomStorageWorkerPoolTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
+  // Note base::TaskRunner implements PostTask in terms of PostDelayedTask
+  // with a delay of zero, we detect that usage and avoid the unecessary
+  // trip thru the message_loop.
+  if (delay == base::TimeDelta()) {
+    // We can skip on shutdown as the destructor of DomStorageArea will ensure
+    // that any remaining data is committed to disk.
+    return sequenced_worker_pool_->PostSequencedWorkerTaskWithShutdownBehavior(
+        sequence_token_, from_here, task,
+        base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+  }
   // Post a task to call this->PostTask() after the delay.
   return message_loop_->PostDelayedTask(
       FROM_HERE,
@@ -81,8 +87,9 @@ bool MockDomStorageTaskRunner::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
-  // Don't wait in unit tests.
-  return PostTask(from_here, task);
+  // Squash all delays to zero in our mock.
+  return DomStorageTaskRunner::PostDelayedTask(
+      from_here, task, base::TimeDelta());
 }
 
 }  // namespace dom_storage
diff --git a/webkit/dom_storage/dom_storage_task_runner.h b/webkit/dom_storage/dom_storage_task_runner.h
index 4c5600e..9fde32f 100644
--- a/webkit/dom_storage/dom_storage_task_runner.h
+++ b/webkit/dom_storage/dom_storage_task_runner.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "base/memory/ref_counted.h"
+#include "base/task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/time.h"
 
@@ -18,23 +19,31 @@ namespace dom_storage {
 
 // Tasks must run serially with respect to one another, but may
 // execute on different OS threads. The base class is implemented
-// in terms of a MessageLoopProxy for use in testing.
-class DomStorageTaskRunner
-    : public base::RefCountedThreadSafe<DomStorageTaskRunner> {
+// in terms of a MessageLoopProxy.
+class DomStorageTaskRunner : public base::TaskRunner {
  public:
   explicit DomStorageTaskRunner(base::MessageLoopProxy* message_loop);
   virtual ~DomStorageTaskRunner();
 
-  // Schedules a task to be run immediately.
-  virtual bool PostTask(
-      const tracked_objects::Location& from_here,
-      const base::Closure& task);
+  // The PostTask() method, defined by TaskRunner, schedules a task
+  // to run immediately.
 
   // Schedules a task to be run after a delay.
   virtual bool PostDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
-      base::TimeDelta delay);
+      base::TimeDelta delay) OVERRIDE;
+
+  // DEPRECATED: Only here because base::TaskRunner requires it, implemented
+  // by calling the virtual PostDelayedTask(..., TimeDelta) variant.
+  virtual bool PostDelayedTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task,
+      int64 delay_ms) OVERRIDE;
+
+  // Only here because base::TaskRunner requires it, the return
+  // value is hard coded to true.
+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
 
  protected:
   const scoped_refptr<base::MessageLoopProxy> message_loop_;
@@ -47,20 +56,18 @@ class DomStorageWorkerPoolTaskRunner : public DomStorageTaskRunner {
  public:
   DomStorageWorkerPoolTaskRunner(
       base::SequencedWorkerPool* sequenced_worker_pool,
+      base::SequencedWorkerPool::SequenceToken sequence_token,
       base::MessageLoopProxy* delayed_task_loop);
   virtual ~DomStorageWorkerPoolTaskRunner();
 
-  // Schedules a sequenced worker task to be run immediately.
-  virtual bool PostTask(
-      const tracked_objects::Location& from_here,
-      const base::Closure& task) OVERRIDE;
-
   // Schedules a sequenced worker task to be run after a delay.
   virtual bool PostDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       base::TimeDelta delay) OVERRIDE;
 
+  base::SequencedWorkerPool::SequenceToken sequence_token() const;
+
  private:
   const scoped_refptr<base::SequencedWorkerPool> sequenced_worker_pool_;
   base::SequencedWorkerPool::SequenceToken sequence_token_;
@@ -72,7 +79,7 @@ class DomStorageWorkerPoolTaskRunner : public DomStorageTaskRunner {
 class MockDomStorageTaskRunner : public DomStorageTaskRunner {
  public:
   explicit MockDomStorageTaskRunner(base::MessageLoopProxy* message_loop);
-  virtual ~MockDomStorageTaskRunner() { }
+  virtual ~MockDomStorageTaskRunner() {}
 
   virtual bool PostDelayedTask(
       const tracked_objects::Location& from_here,