Correcly Report CanEnterMaximizeMode on devices without accelerometers

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"
@@ skipping 185 matching lines @@
   // startup.
   base::PostTaskAndReplyWithResult(
       task_runner_.get(), FROM_HERE,
       base::Bind(&DetectAndReadAccelerometerConfiguration, configuration_),
       base::Bind(&AccelerometerReader::OnInitialized,
                  weak_factory_.GetWeakPtr(), configuration_));
 }
 
 void AccelerometerReader::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
-  observer->OnAccelerometerUpdated(update_);
+  if (update_.has(chromeos::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD) ||
+      update_.has(chromeos::ACCELEROMETER_SOURCE_SCREEN)) {

[flackr, 2015/02/04 18:44:52]

I'd prefer adding a bool for if it has gotten a reading yet (i.e. if
AccelerometerReader::OnDataRead has been called with success == true).

[jonross, 2015/02/04 19:00:59]

Done.

+    observer->OnAccelerometerUpdated(update_);
+  }
 }
 
 void AccelerometerReader::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 AccelerometerReader::AccelerometerReader()
     : configuration_(new AccelerometerReader::Configuration()),
       weak_factory_(this) {
 }
@@ skipping 46 matching lines @@
 
   // 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