Refactor AccelerometerReader to provide an Observer

chromeos/accelerometer/accelerometer_reader.cc

 // Copyright 2014 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 "chromeos/accelerometer/accelerometer_reader.h"
 
+#include <string>
+
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/task_runner.h"
 #include "base/task_runner_util.h"
 #include "base/threading/sequenced_worker_pool.h"
@@ skipping 157 matching lines @@
     for (int j = 0; j < 3; ++j) {
       scale[i][j] = 0;
       index[i][j] = -1;
     }
   }
 }
 
 AccelerometerReader::ConfigurationData::~ConfigurationData() {
 }
 
-AccelerometerReader::AccelerometerReader(
-    scoped_refptr<base::TaskRunner> blocking_task_runner,
-    AccelerometerReader::Delegate* delegate)
-    : task_runner_(blocking_task_runner),
-      delegate_(delegate),
-      configuration_(new AccelerometerReader::Configuration()),
+AccelerometerReader::AccelerometerReader()
+    : configuration_(new AccelerometerReader::Configuration()),
       weak_factory_(this) {
-  DCHECK(task_runner_.get());
-  DCHECK(delegate_);
+}
+
+AccelerometerReader::~AccelerometerReader() {
+}
+
+void AccelerometerReader::Initialize(
+    scoped_refptr<base::TaskRunner> blocking_task_runner) {
+  DCHECK(blocking_task_runner.get());
+  task_runner_ = blocking_task_runner;
   // Asynchronously detect and initialize the accelerometer to avoid delaying
   // startup.
-  base::PostTaskAndReplyWithResult(task_runner_.get(), FROM_HERE,
+  base::PostTaskAndReplyWithResult(
+      task_runner_.get(), FROM_HERE,
       base::Bind(&DetectAndReadAccelerometerConfiguration, configuration_),
       base::Bind(&AccelerometerReader::OnInitialized,
                  weak_factory_.GetWeakPtr(), configuration_));
 }
 
-AccelerometerReader::~AccelerometerReader() {
+void AccelerometerReader::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void AccelerometerReader::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
 }
 
 void AccelerometerReader::OnInitialized(
     scoped_refptr<AccelerometerReader::Configuration> configuration,
     bool success) {
   if (success)
     TriggerRead();
 }
 
 void AccelerometerReader::TriggerRead() {
@@ skipping 22 matching lines @@
 
       int16* values = reinterpret_cast<int16*>(reading->data);
       update_.Set(static_cast<ui::AccelerometerSource>(i),
                   values[configuration_->data.index[i][0]] *
                       configuration_->data.scale[i][0],
                   values[configuration_->data.index[i][1]] *
                       configuration_->data.scale[i][1],
                   values[configuration_->data.index[i][2]] *
                       configuration_->data.scale[i][2]);
     }
-    delegate_->HandleAccelerometerUpdate(update_);
+    FOR_EACH_OBSERVER(Observer, observers_, OnAccelerometerUpdated(update_));
   }
 
   // Trigger another read after the current sampling delay.
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&AccelerometerReader::TriggerRead,
                  weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kDelayBetweenReadsMs));
 }
 
 }  // namespace chromeos