power: Add GetKeyboardBrightnessPercent

Adds a GetKeyboardBrightnessPercent method to the PowerManagerClient
interface. This method was added in order to track keyboard energy
consumption over time so that chrome://power could approximate power
usage of other devices over time.

keyboard brightness change as you increase and decrease your keyboard
brightness.

BUG: crbug.com/851767
TEST: Call this method inside Chrome on a Chrome OS device and see the
Change-Id: I35323708da1e0bcc9b4549b85ad6e2d8ad215af5
Reviewed-on: https://chromium-review.googlesource.com/1120839Reviewed-by: Dan Erat <derat@chromium.org>
Commit-Queue: Nikhil Athreya <nathreya@google.com>
Cr-Commit-Position: refs/heads/master@{#572025}

chromeos/dbus/fake_power_manager_client.cc

@@ -102,6 +102,13 @@ void FakePowerManagerClient::DecreaseKeyboardBrightness() {}
 
 void FakePowerManagerClient::IncreaseKeyboardBrightness() {}
 
+void FakePowerManagerClient::GetKeyboardBrightnessPercent(
+    DBusMethodCallback<double> callback) {
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::BindOnce(std::move(callback), keyboard_brightness_percent_));
+}
+
 const base::Optional<power_manager::PowerSupplyProperties>&
 FakePowerManagerClient::GetLastStatus() {
   return props_;

chromeos/dbus/fake_power_manager_client.h

@@ -78,6 +78,8 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
   void GetScreenBrightnessPercent(DBusMethodCallback<double> callback) override;
   void DecreaseKeyboardBrightness() override;
   void IncreaseKeyboardBrightness() override;
+  void GetKeyboardBrightnessPercent(
+      DBusMethodCallback<double> callback) override;
   const base::Optional<power_manager::PowerSupplyProperties>& GetLastStatus()
       override;
   void RequestStatusUpdate() override;
@@ -164,6 +166,10 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
     screen_brightness_percent_ = percent;
   }
 
+  void set_keyboard_brightness_percent(const base::Optional<double>& percent) {
+    keyboard_brightness_percent_ = percent;
+  }
+
  private:
   // Callback that will be run by asynchronous suspend delays to report
   // readiness.
@@ -193,6 +199,9 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
   // Current screen brightness in the range [0.0, 100.0].
   base::Optional<double> screen_brightness_percent_;
 
+  // Current keyboard brightness in the range [0.0, 100.0].
+  base::Optional<double> keyboard_brightness_percent_;
+
   // Last screen brightness requested via SetScreenBrightnessPercent().
   // Unlike |screen_brightness_percent_|, this value will not be changed by
   // SetBacklightsForcedOff() method - a method that implicitly changes screen

chromeos/dbus/power_manager_client.cc

@@ -228,7 +228,20 @@ class PowerManagerClientImpl : public PowerManagerClient {
         power_manager::kGetScreenBrightnessPercentMethod);
     power_manager_proxy_->CallMethod(
         &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
-        base::BindOnce(&PowerManagerClientImpl::OnGetScreenBrightnessPercent,
+        base::BindOnce(
+            &PowerManagerClientImpl::OnGetScreenOrKeyboardBrightnessPercent,
+            weak_ptr_factory_.GetWeakPtr(), std::move(callback)));
+  }
+
+  void GetKeyboardBrightnessPercent(
+      DBusMethodCallback<double> callback) override {
+    dbus::MethodCall method_call(
+        power_manager::kPowerManagerInterface,
+        power_manager::kGetKeyboardBrightnessPercentMethod);
+    power_manager_proxy_->CallMethod(
+        &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::BindOnce(
+            &PowerManagerClientImpl::OnGetScreenOrKeyboardBrightnessPercent,
             weak_ptr_factory_.GetWeakPtr(), std::move(callback)));
   }
 
@@ -648,13 +661,10 @@ class PowerManagerClientImpl : public PowerManagerClient {
     }
   }
 
-  void OnGetScreenBrightnessPercent(DBusMethodCallback<double> callback,
+  void OnGetScreenOrKeyboardBrightnessPercent(
+      DBusMethodCallback<double> callback,
       dbus::Response* response) {
     if (!response) {
-      if (!system::StatisticsProvider::GetInstance()->IsRunningOnVm()) {
-        POWER_LOG(ERROR) << "Error calling "
-                         << power_manager::kGetScreenBrightnessPercentMethod;
-      }
       std::move(callback).Run(base::nullopt);
       return;
     }

chromeos/dbus/power_manager_client.h

@@ -192,6 +192,11 @@ class CHROMEOS_EXPORT PowerManagerClient : public DBusClient {
   // Increases the keyboard brightness.
   virtual void IncreaseKeyboardBrightness() = 0;
 
+  // Similar to GetScreenBrightnessPercent, but gets the keyboard brightness
+  // instead.
+  virtual void GetKeyboardBrightnessPercent(
+      DBusMethodCallback<double> callback) = 0;
+
   // Returns the last power status that was received from D-Bus, if any.
   virtual const base::Optional<power_manager::PowerSupplyProperties>&
   GetLastStatus() = 0;