Add button to toggle passphrase visibility

closes #3776
// FREEBIE

res/layout/prompt_passphrase_activity.xml

@@ -32,7 +32,40 @@
                       android:layout_marginRight="50dp"
                       android:singleLine="true"
                       android:paddingLeft="10dp"
-                      android:paddingRight="10dp"/>
+                      android:paddingRight="40dp"/>
+
+            <org.thoughtcrime.securesms.components.AnimatingToggle
+                    android:id="@+id/button_toggle"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_alignRight="@+id/passphrase_edit"
+                    android:layout_centerVertical="true"
+                    android:layout_gravity="center"
+                    android:gravity="center">
+
+                <ImageButton android:id="@+id/passphrase_visibility"
+                             android:src="?ic_visibility"
+                             android:background="@drawable/touch_highlight_background"
+                             android:layout_width="wrap_content"
+                             android:layout_height="wrap_content"
+                             android:paddingLeft="8dp"
+                             android:paddingRight="8dp"
+                             android:paddingTop="3dp"
+                             android:paddingBottom="3dp"
+                             android:layout_centerVertical="true" />
+
+                <ImageButton android:id="@+id/passphrase_visibility_off"
+                             android:src="?ic_visibility_off"
+                             android:background="@drawable/touch_highlight_background"
+                             android:layout_width="wrap_content"
+                             android:layout_height="wrap_content"
+                             android:paddingLeft="8dp"
+                             android:paddingRight="8dp"
+                             android:paddingTop="3dp"
+                             android:paddingBottom="3dp"
+                             android:layout_centerVertical="true" />
+
+            </org.thoughtcrime.securesms.components.AnimatingToggle>
 
             <ImageButton android:id="@+id/ok_button"
                          android:src="?ic_arrow_forward"

res/values/attrs.xml

@@ -23,6 +23,8 @@
 
     <attr name="centered_app_title_color" format="reference|color" />
     <attr name="ic_arrow_forward" format="reference" />
+    <attr name="ic_visibility" format="reference" />
+    <attr name="ic_visibility_off" format="reference" />
 
     <attr name="conversation_background" format="reference|color"/>
     <attr name="conversation_editor_background" format="reference|color"/>

res/values/themes.xml

@@ -46,6 +46,8 @@
         <item name="centered_app_title_color">#55000000</item>
         <item name="ic_arrow_forward">@drawable/ic_arrow_forward_light</item>
         <item name="lockscreen_watermark">@drawable/lockscreen_watermark_light</item>
+        <item name="ic_visibility">@drawable/ic_visibility_grey600_24dp</item>
+        <item name="ic_visibility_off">@drawable/ic_visibility_off_grey600_24dp</item>
     </style>
 
     <style name="TextSecure.DarkIntroTheme" parent="@style/Theme.AppCompat">
@@ -57,6 +59,8 @@
         <item name="ic_arrow_forward">@drawable/ic_arrow_forward_dark</item>
         <item name="lockscreen_watermark">@drawable/lockscreen_watermark_dark</item>
         <item name="android:windowBackground">@color/black</item>
+        <item name="ic_visibility">@drawable/ic_visibility_white_24dp</item>
+        <item name="ic_visibility_off">@drawable/ic_visibility_off_white_24dp</item>
     </style>
 
     <style name="PopupAnimation" parent="@android:style/Animation">