base::Bind() conversion for MetricsService.

chrome/browser/metrics/histogram_synchronizer.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/metrics/histogram_synchronizer.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/threading/thread.h"
@@ skipping 10 matching lines @@
 // Negative numbers are never used as sequence numbers.  We explicitly pick a
 // negative number that is "so negative" that even when we add one (as is done
 // when we generated the next sequence number) that it will still be negative.
 // We have code that handles wrapping around on an overflow into negative
 // territory.
 static const int kNeverUsableSequenceNumber = -2;
 
 HistogramSynchronizer::HistogramSynchronizer()
   : lock_(),
     received_all_renderer_histograms_(&lock_),
-    callback_task_(NULL),
     callback_thread_(NULL),
     last_used_sequence_number_(kNeverUsableSequenceNumber),
     async_sequence_number_(kNeverUsableSequenceNumber),
     async_renderers_pending_(0),
     synchronous_sequence_number_(kNeverUsableSequenceNumber),
     synchronous_renderers_pending_(0) {
   DCHECK(histogram_synchronizer_ == NULL);
   histogram_synchronizer_ = this;
 }
 
 HistogramSynchronizer::~HistogramSynchronizer() {
   // Just in case we have any pending tasks, clear them out.
-  SetCallbackTaskAndThread(NULL, NULL);
+  SetCallbackTaskAndThread(NULL, base::Closure());
   histogram_synchronizer_ = NULL;
 }
 
 // static
 HistogramSynchronizer* HistogramSynchronizer::CurrentSynchronizer() {
   DCHECK(histogram_synchronizer_ != NULL);
   return histogram_synchronizer_;
 }
 
 void HistogramSynchronizer::FetchRendererHistogramsSynchronously(
@@ skipping 16 matching lines @@
   UMA_HISTOGRAM_COUNTS("Histogram.RendersNotRespondingSynchronous",
                        unresponsive_renderer_count);
   if (!unresponsive_renderer_count)
     UMA_HISTOGRAM_TIMES("Histogram.FetchRendererHistogramsSynchronously",
                         TimeTicks::Now() - start);
 }
 
 // static
 void HistogramSynchronizer::FetchRendererHistogramsAsynchronously(
     MessageLoop* callback_thread,
-    Task* callback_task,
+    const base::Closure& callback,
     int wait_time) {
   DCHECK(callback_thread != NULL);
-  DCHECK(callback_task != NULL);
+  DCHECK(!callback.is_null());
 
   HistogramSynchronizer* current_synchronizer = CurrentSynchronizer();
 
   if (current_synchronizer == NULL) {
     // System teardown is happening.
-    callback_thread->PostTask(FROM_HERE, callback_task);
+    callback_thread->PostTask(FROM_HERE, callback);
     return;
   }
 
   current_synchronizer->SetCallbackTaskAndThread(callback_thread,
-                                                 callback_task);
+                                                 callback);
 
   int sequence_number =
       current_synchronizer->NotifyAllRenderers(ASYNC_HISTOGRAMS);
 
   // Post a task that would be called after waiting for wait_time.  This acts
   // as a watchdog, to ensure that a non-responsive renderer won't block us from
   // making the callback.
   BrowserThread::PostDelayedTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(
@@ skipping 63 matching lines @@
   }
 
   if (asynchronous_completed)
     ForceHistogramSynchronizationDoneCallback(sequence_number);
   else if (synchronous_completed)
     received_all_renderer_histograms_.Signal();
 }
 
 void HistogramSynchronizer::SetCallbackTaskAndThread(
     MessageLoop* callback_thread,
-    Task* callback_task) {
-  Task* old_task = NULL;
+    const base::Closure& callback) {
+  base::Closure old_callback;
   MessageLoop* old_thread = NULL;
   TimeTicks old_start_time;
   int unresponsive_renderers;
   const TimeTicks now = TimeTicks::Now();
   {
     base::AutoLock auto_lock(lock_);
-    old_task = callback_task_;
-    callback_task_ = callback_task;
+    old_callback = callback_;
+    callback_ = callback;
     old_thread = callback_thread_;
     callback_thread_ = callback_thread;
     unresponsive_renderers = async_renderers_pending_;
     old_start_time = async_callback_start_time_;
     async_callback_start_time_ = now;
     // Prevent premature calling of our new callbacks.
     async_sequence_number_ = kNeverUsableSequenceNumber;
   }
   // Just in case there was a task pending....
-  InternalPostTask(old_thread, old_task, unresponsive_renderers,
+  InternalPostTask(old_thread, old_callback, unresponsive_renderers,
                    old_start_time);
 }
 
 void HistogramSynchronizer::ForceHistogramSynchronizationDoneCallback(
     int sequence_number) {
-  Task* task = NULL;
+  base::Closure callback;
   MessageLoop* thread = NULL;
   TimeTicks started;
   int unresponsive_renderers;
   {
     base::AutoLock lock(lock_);
     if (sequence_number != async_sequence_number_)
       return;
-    task = callback_task_;
+    callback = callback_;
     thread = callback_thread_;
-    callback_task_ = NULL;
+    callback_.Reset();
     callback_thread_ = NULL;
     started = async_callback_start_time_;
     unresponsive_renderers = async_renderers_pending_;
   }
-  InternalPostTask(thread, task, unresponsive_renderers, started);
+  InternalPostTask(thread, callback, unresponsive_renderers, started);
 }
 
-void HistogramSynchronizer::InternalPostTask(MessageLoop* thread, Task* task,
+void HistogramSynchronizer::InternalPostTask(MessageLoop* thread,
+                                             const base::Closure& callback,
                                              int unresponsive_renderers,
                                              const base::TimeTicks& started) {
-  if (!task || !thread)
+  if (callback.is_null() || !thread)
     return;
   UMA_HISTOGRAM_COUNTS("Histogram.RendersNotRespondingAsynchronous",
                        unresponsive_renderers);
   if (!unresponsive_renderers) {
     UMA_HISTOGRAM_TIMES("Histogram.FetchRendererHistogramsAsynchronously",
                         TimeTicks::Now() - started);
   }
 
-  thread->PostTask(FROM_HERE, task);
+  thread->PostTask(FROM_HERE, callback);
 }
 
 int HistogramSynchronizer::GetNextAvailableSequenceNumber(
     RendererHistogramRequester requester,
     int renderer_count) {
   base::AutoLock auto_lock(lock_);
   ++last_used_sequence_number_;
   // Watch out for wrapping to a negative number.
   if (last_used_sequence_number_ < 0) {
     // Bypass the reserved number, which is used when a renderer spontaneously
     // decides to send some histogram data.
     last_used_sequence_number_ =
         chrome::kHistogramSynchronizerReservedSequenceNumber + 1;
   }
   DCHECK_NE(last_used_sequence_number_,
             chrome::kHistogramSynchronizerReservedSequenceNumber);
   if (requester == ASYNC_HISTOGRAMS) {
     async_sequence_number_ = last_used_sequence_number_;
     async_renderers_pending_ = renderer_count;
   } else if (requester == SYNCHRONOUS_HISTOGRAMS) {
     synchronous_sequence_number_ = last_used_sequence_number_;
     synchronous_renderers_pending_ = renderer_count;
   }
   return last_used_sequence_number_;
 }
 
 // static
 HistogramSynchronizer* HistogramSynchronizer::histogram_synchronizer_ = NULL;