[Quantum compose] autoscroll to cc

On phones when the user taps on subject/body with cc/bcc,
we autoscroll so that cc aligns with the top and the subject/
body have enough space to not feel clumped.

b/15934812

Change-Id: I5c44b409fd89e9e810bfc07d935579d36626e87d
diff --git a/res/values/constants.xml b/res/values/constants.xml
index 73ebde3..6a3623b 100644
--- a/res/values/constants.xml
+++ b/res/values/constants.xml
@@ -118,4 +118,6 @@
 
     <!-- Used to force 70% of max width in compose for landscape tablet -->
     <integer name="compose_padding_weight">0</integer>
+    <!-- Whether or not we should scroll down so cc aligns with the top -->
+    <bool name="auto_scroll_cc">true</bool>
 </resources>