Setting: Developer Option: Adds a low power mode checkbox

Change-Id: I489f74bd3822f64acb8becd6e5eda716d8bd722c
Signed-off-by: Ruchi Kandoi<kandoiruchi@google.com>

res/values/strings.xml

@@ -4421,6 +4421,11 @@
     <!-- UI debug setting: force right to left layout summary [CHAR LIMIT=100] -->
     <string name="force_rtl_layout_all_locales_summary">Force screen layout direction to RTL for all locales</string>
 
+    <!-- UI debug setting: start low power mode [CHAR LIMIT=25] -->
+    <string name="low_power_mode">Low Power Mode</string>
+    <!-- UI debug setting: start low power mode summary[CHAR LIMIT=50] -->
+    <string name="low_power_mode_summary">Enable battery saving settings</string>
+
     <!-- UI debug setting: show how CPU is being used? [CHAR LIMIT=25] -->
     <string name="show_cpu_usage">Show CPU usage</string>
     <!-- UI debug setting: show cpu usage summary [CHAR LIMIT=50] -->

res/xml/development_prefs.xml

@@ -240,6 +240,11 @@
             android:title="@string/strict_mode"
             android:summary="@string/strict_mode_summary"/>
 
+        <CheckBoxPreference
+            android:key="low_power_mode"
+            android:title="@string/low_power_mode"
+            android:summary="@string/low_power_mode_summary"/>
+
         <CheckBoxPreference
             android:key="show_cpu_usage"
             android:title="@string/show_cpu_usage"

src/com/android/settings/DevelopmentSettings.java

@@ -118,6 +118,7 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
     private static final String USE_NUPLAYER_KEY = "use_nuplayer";
     private static final String USE_NUPLAYER_PROPERTY = "persist.sys.media.use-nuplayer";
     private static final String SHOW_CPU_USAGE_KEY = "show_cpu_usage";
+    private static final String LOW_POWER_MODE_KEY = "low_power_mode";
     private static final String FORCE_HARDWARE_UI_KEY = "force_hw_ui";
     private static final String FORCE_MSAA_KEY = "force_msaa";
     private static final String TRACK_FRAME_TIME_KEY = "track_frame_time";
@@ -184,6 +185,7 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
     private CheckBoxPreference mShowScreenUpdates;
     private CheckBoxPreference mDisableOverlays;
     private CheckBoxPreference mShowCpuUsage;
+    private CheckBoxPreference mLowPowerMode;
     private CheckBoxPreference mForceHardwareUi;
     private CheckBoxPreference mForceMsaa;
     private CheckBoxPreference mShowHwScreenUpdates;
@@ -293,6 +295,7 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
         mShowScreenUpdates = findAndInitCheckboxPref(SHOW_SCREEN_UPDATES_KEY);
         mDisableOverlays = findAndInitCheckboxPref(DISABLE_OVERLAYS_KEY);
         mShowCpuUsage = findAndInitCheckboxPref(SHOW_CPU_USAGE_KEY);
+        mLowPowerMode = findAndInitCheckboxPref(LOW_POWER_MODE_KEY);
         mForceHardwareUi = findAndInitCheckboxPref(FORCE_HARDWARE_UI_KEY);
         mForceMsaa = findAndInitCheckboxPref(FORCE_MSAA_KEY);
         mTrackFrameTime = addListPreference(TRACK_FRAME_TIME_KEY);
@@ -497,6 +500,7 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
         updateShowTouchesOptions();
         updateFlingerOptions();
         updateCpuUsageOptions();
+        updateLowPowerModeOptions();
         updateHardwareUiOptions();
         updateMsaaOptions();
         updateTrackFrameTimeOptions();
@@ -1021,11 +1025,22 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
                 mWifiDisplayCertification.isChecked() ? 1 : 0);
     }
 
+    private void updateLowPowerModeOptions() {
+        updateCheckBox(mLowPowerMode, Settings.Global.getInt(getActivity().getContentResolver(),
+                Settings.Global.LOW_POWER_MODE, 0) != 0);
+    }
+
     private void updateCpuUsageOptions() {
         updateCheckBox(mShowCpuUsage, Settings.Global.getInt(getActivity().getContentResolver(),
                 Settings.Global.SHOW_PROCESSES, 0) != 0);
     }
 
+    private void writeLowPowerModeOptions() {
+        boolean value = mLowPowerMode.isChecked();
+        Settings.Global.putInt(getActivity().getContentResolver(),
+                Settings.Global.LOW_POWER_MODE, value ? 1 : 0);
+    }
+
     private void writeCpuUsageOptions() {
         boolean value = mShowCpuUsage.isChecked();
         Settings.Global.putInt(getActivity().getContentResolver(),
@@ -1286,6 +1301,8 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
             writeShowUpdatesOption();
         } else if (preference == mDisableOverlays) {
             writeDisableOverlaysOption();
+        } else if (preference == mLowPowerMode) {
+            writeLowPowerModeOptions();
         } else if (preference == mShowCpuUsage) {
             writeCpuUsageOptions();
         } else if (preference == mImmediatelyDestroyActivities) {