Add a power saving mode setting

Create a setting that tunes performance optimizations and improves the
power usage.
Automatically tune mode with the Power-saving mode of Android Lollipop+.
Also, when the phone drops below threshold for low battery, prompt user
to turn browser's power save mode on.

Change-Id: I64089a371de562f9a18c297eb09555733f020515

5 files changed, 20 insertions, 1 deletions

diff --git a/res/values-zh-rCN/strings.xml b/res/values-zh-rCN/strings.xml
index d04560a8..ad0b7507 100644
--- a/res/values-zh-rCN/strings.xml
+++ b/res/values-zh-rCN/strings.xml
@@ -150,6 +150,8 @@
     <string name="pref_do_not_track">"不跟踪"</string>
     <string name="pref_do_not_track_summary">"随浏览流量发送"请勿跟踪"请求"</string>
     <string name="pref_sample_font_size">"拖动该滑块，将文字调整到适合您阅读的大小。点按两次某段落后，文字至少应该显示为这样的字体大小。"</string>
+    <string name="pref_powersave_enabled">"省电模式"</string>
+    <string name="pref_powersave_enabled_summary">"开启省电模式"</string>
 
   <string-array name="pref_content_plugins_choices">
     <item msgid="6745108155096660725">"始终启用（打开）"</item>
diff --git a/res/values-zh-rHK/strings.xml b/res/values-zh-rHK/strings.xml
index 57d90922..587921cb 100644
--- a/res/values-zh-rHK/strings.xml
+++ b/res/values-zh-rHK/strings.xml
@@ -145,7 +145,8 @@
     <string name="ssl_certificate">安全性憑證</string>
     <string name="ssl_certificate_is_valid">此憑證有效。</string>
     <string name="pref_memory_monitor">啟用記憶體監察器</string>
-
+    <string name="pref_powersave_enabled">"省電模式"</string>
+    <string name="pref_powersave_enabled_summary">"開啟省電模式"</string>
 
   <string-array name="pref_content_plugins_choices">
     <item msgid="6745108155096660725">"永遠開啟"</item>
diff --git a/res/values-zh-rTW/strings.xml b/res/values-zh-rTW/strings.xml
index 2fa98a52..3ff67087 100644
--- a/res/values-zh-rTW/strings.xml
+++ b/res/values-zh-rTW/strings.xml
@@ -136,6 +136,11 @@
     <string name="pref_content_javascript" msgid="4570972030299516843">"啟用 JavaScript"</string>
     <string name="pref_content_open_in_background" msgid="824123779725118663">"在背景中開啟"</string>
     <string name="pref_content_plugins" msgid="7231944644794301582">"啟用外掛程式"</string>
+
+    <!-- Custom Translations -->
+    <string name="pref_powersave_enabled">"省電模式"</string>
+    <string name="pref_powersave_enabled_summary">"開啟省電模式"</string>
+
   <string-array name="pref_content_plugins_choices">
     <item msgid="6745108155096660725">"永遠開啟"</item>
     <item msgid="2484126708670016519">"隨選"</item>
diff --git a/res/values/strings.xml b/res/values/strings.xml
index cc63a709..62b31d7e 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -380,6 +380,11 @@
     <!-- Settings category for autofill under general. [CHAR-LIMIT=50] -->
     <string name="pref_general_autofill_title">Auto-fill</string>
 
+    <!-- Checkbox setting for enabling/disabling power save mode feature -->
+    <string name ="pref_powersave_enabled">Power save mode</string>
+    <!-- Settings summary for the powersave feature. -->
+    <string name ="pref_powersave_enabled_summary">Turn on power saving mode</string>
+
     <!-- Checkbox setting for enabling/disabling the form AutoFill feature [CHAR-LIMIT=32] -->
     <string name="pref_autofill_enabled">Form auto-fill</string>
     <!-- Settings summary for the form AutoFill feature. [CHAR-LIMIT=none] -->
diff --git a/res/xml/general_preferences.xml b/res/xml/general_preferences.xml
index a1f2d256..d0bf5334 100644
--- a/res/xml/general_preferences.xml
+++ b/res/xml/general_preferences.xml
@@ -37,6 +37,12 @@
             android:title="@string/pref_lab_fullscreen" />
 
         <CheckBoxPreference
+            android:defaultValue="false"
+            android:key="powersave_enabled"
+            android:summary="@string/pref_powersave_enabled_summary"
+            android:title="@string/pref_powersave_enabled" />
+
+        <CheckBoxPreference
             android:key="autofill_enabled"
             android:title="@string/pref_autofill_enabled"
             android:summary="@string/pref_autofill_enabled_summary"