Chromium: Use GetAttributes in SensorDevice

Updating with CL:2494163, this commit replaces GetAttribute with
GetAttributes so that sensor clients can get multiple attributes within
one Mojo request.

BUG=chromium:1006141, b:162154663
TEST=builds and run ash on octopus

Change-Id: I33fb315050b5aaefa8e387a8afcdc2aa1c9ca2da
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490320Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Cheng-Hao Yang <chenghaoyang@chromium.org>
Auto-Submit: Cheng-Hao Yang <chenghaoyang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820263}

chromeos/components/sensors/fake_sensor_device.cc

@@ -66,17 +66,22 @@ void FakeSensorDevice::SetChannels(const std::vector<ChannelData>& channels) {
   channels_enabled_.assign(channels_.size(), false);
 }
 
-void FakeSensorDevice::GetAttribute(const std::string& attr_name,
-                                    GetAttributeCallback callback) {
+void FakeSensorDevice::GetAttributes(const std::vector<std::string>& attr_names,
+                                     GetAttributesCallback callback) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-  base::Optional<std::string> value = base::nullopt;
+  std::vector<base::Optional<std::string>> values;
+  values.reserve(attr_names.size());
+  for (const auto& attr_name : attr_names) {
     auto it = attributes_.find(attr_name);
     if (it != attributes_.end())
-    value = it->second;
+      values.push_back(it->second);
+    else
+      values.push_back(base::nullopt);
+  }
 
   base::SequencedTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::BindOnce(std::move(callback), std::move(value)));
+      FROM_HERE, base::BindOnce(std::move(callback), std::move(values)));
 }
 
 void FakeSensorDevice::SetFrequency(double frequency,

chromeos/components/sensors/fake_sensor_device.h

@@ -48,8 +48,8 @@ class FakeSensorDevice final : public mojom::SensorDevice {
 
   // Implementation of mojom::SensorDevice.
   void SetTimeout(uint32_t timeout) override {}
-  void GetAttribute(const std::string& attr_name,
-                    GetAttributeCallback callback) override;
+  void GetAttributes(const std::vector<std::string>& attr_names,
+                     GetAttributesCallback callback) override;
   void SetFrequency(double frequency, SetFrequencyCallback callback) override;
   void StartReadingSamples(
       mojo::PendingRemote<mojom::SensorDeviceSamplesObserver> observer)

chromeos/components/sensors/mojom/sensor.mojom

@@ -71,9 +71,10 @@ interface SensorDevice {
   // Default: 5000 milliseconds.
   SetTimeout@0(uint32 timeout);
 
-  // Gets the |attr_name| attribute of this device into |value| in string.
-  // Returns base::nullopt if the attribute cannot be read.
-  GetAttribute@1(string attr_name) => (string? value);
+  // Gets the |attr_names| attributes of this device into |values| as strings.
+  // When an attribute cannot be read, its value in |values| is set to null.
+  // |values| and |attr_names| always have the same size.
+  GetAttributes@1(array<string> attr_names) => (array<string?> values);
 
   // Sets the frequency in Hz of the device before starting to read samples.
   // If no frequency or an invalid frequency is set, an