ui: color cleanup

Change-Id: I1d827cf753400e1b36c039df90fac53555a1e5c4
diff --git a/ring-android/app/src/main/res/drawable/ic_online_indicator.xml b/ring-android/app/src/main/res/drawable/ic_online_indicator.xml
index dcf7556..83c1af0 100644
--- a/ring-android/app/src/main/res/drawable/ic_online_indicator.xml
+++ b/ring-android/app/src/main/res/drawable/ic_online_indicator.xml
@@ -1,7 +1,7 @@
 <shape xmlns:android="http://schemas.android.com/apk/res/android"
     android:shape="oval">
-    <stroke android:width="2dp" android:color="#fafafa"/>
-    <solid android:color="#4CAF50" />
+    <stroke android:width="2dp" android:color="@color/background"/>
+    <solid android:color="@color/green_A700" />
     <size
         android:width="16dp"
         android:height="16dp" />
diff --git a/ring-android/app/src/main/res/layout/camerapicker.xml b/ring-android/app/src/main/res/layout/camerapicker.xml
index 3333559..decf767 100644
--- a/ring-android/app/src/main/res/layout/camerapicker.xml
+++ b/ring-android/app/src/main/res/layout/camerapicker.xml
@@ -17,7 +17,7 @@
         android:layout_centerHorizontal="true"
         android:contentDescription="@string/action_call_decline"
         android:padding="16dp"
-        app:backgroundTint="@color/holo_green_dark"
+        app:backgroundTint="@color/green_500"
         app:rippleColor="@android:color/white"
         app:srcCompat="@drawable/baseline_photo_camera_24"
         app:useCompatPadding="true" />
diff --git a/ring-android/app/src/main/res/layout/frag_call.xml b/ring-android/app/src/main/res/layout/frag_call.xml
index cba46e4..a2dfc70 100644
--- a/ring-android/app/src/main/res/layout/frag_call.xml
+++ b/ring-android/app/src/main/res/layout/frag_call.xml
@@ -178,7 +178,7 @@
                     android:contentDescription="@string/action_call_accept"
                     android:onClick="@{() -> presenter.acceptClicked()}"
                     android:visibility="gone"
-                    app:backgroundTint="#4caf50"
+                    app:backgroundTint="@color/green_500"
                     app:elevation="6dp"
                     app:fabSize="normal"
                     app:pressedTranslationZ="12dp"
diff --git a/ring-android/app/src/main/res/values/colors.xml b/ring-android/app/src/main/res/values/colors.xml
index b33bea8..981b7fa 100644
--- a/ring-android/app/src/main/res/values/colors.xml
+++ b/ring-android/app/src/main/res/values/colors.xml
@@ -32,11 +32,6 @@
 
     <color name="transparent_light">#AAFFFFFF</color>
 
-    <!-- A light Holo shade of red -->
-    <color name="holo_red_light">#ffff4444</color>
-    <!-- A dark Holo shade of green -->
-    <color name="holo_green_dark">#ff669900</color>
-
     <color name="transparent_grey">#AACCCCCC</color>
     <color name="transparent_dark_grey">#88424242</color>