call: allow to drag video preview

Change-Id: I49413a061fcd5bef2056656d8276b48477aa522f
diff --git a/ring-android/app/src/main/res/values/dimens.xml b/ring-android/app/src/main/res/values/dimens.xml
index 74d5110..b48f676 100644
--- a/ring-android/app/src/main/res/values/dimens.xml
+++ b/ring-android/app/src/main/res/values/dimens.xml
@@ -69,4 +69,8 @@
 
     <dimen name="navigation_bottom_height">60dp</dimen>
 
+    <dimen name="call_preview_elevation">8dp</dimen>
+    <dimen name="call_preview_elevation_dragged">16dp</dimen>
+    <dimen name="call_preview_margin">12dp</dimen>
+
 </resources>
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