Add a density axis to tapas.

It allows overriding the density the app
is built for. Currently only used in the
GMS core APK's gradle file.

Change-Id: I3606df313a3110208cd8e6acade5f558261c921f
(cherry picked from commit 7e3d2341570681e566872216796dc4f79c8695ef)
diff --git a/envsetup.sh b/envsetup.sh
index a9bd707..f4c6566 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -570,7 +570,8 @@
 {
     local arch="$(echo $* | xargs -n 1 echo | \grep -E '^(arm|x86|mips|armv5|arm64|x86_64|mips64)$' | xargs)"
     local variant="$(echo $* | xargs -n 1 echo | \grep -E '^(user|userdebug|eng)$' | xargs)"
-    local apps="$(echo $* | xargs -n 1 echo | \grep -E -v '^(user|userdebug|eng|arm|x86|mips|armv5|arm64|x86_64|mips64)$' | xargs)"
+    local density="$(echo $* | xargs -n 1 echo | \grep -E '^(ldpi|mdpi|tvdpi|hdpi|xhdpi|xxhdpi|xxxhdpi|alldpi)$' | xargs)"
+    local apps="$(echo $* | xargs -n 1 echo | \grep -E -v '^(user|userdebug|eng|arm|x86|mips|armv5|arm64|x86_64|mips64|ldpi|mdpi|tvdpi|hdpi|xhdpi|xxhdpi|xxxhdpi|alldpi)$' | xargs)"
 
     if [ $(echo $arch | wc -w) -gt 1 ]; then
         echo "tapas: Error: Multiple build archs supplied: $arch"
@@ -580,6 +581,10 @@
         echo "tapas: Error: Multiple build variants supplied: $variant"
         return
     fi
+    if [ $(echo $density | wc -w) -gt 1 ]; then
+        echo "tapas: Error: Multiple densities supplied: $density"
+        return
+    fi
 
     local product=full
     case $arch in
@@ -599,6 +604,7 @@
 
     export TARGET_PRODUCT=$product
     export TARGET_BUILD_VARIANT=$variant
+    export TARGET_BUILD_DENSITY=$density
     export TARGET_BUILD_TYPE=release
     export TARGET_BUILD_APPS=$apps