Add "tv" density for 720p screens.

Change-Id: I028969b007f2fceea66947d77a2ae31ef1d1a630
diff --git a/tools/aapt/AaptAssets.cpp b/tools/aapt/AaptAssets.cpp
index 4894196..29d2b87 100644
--- a/tools/aapt/AaptAssets.cpp
+++ b/tools/aapt/AaptAssets.cpp
@@ -969,6 +969,11 @@
         return true;
     }
     
+    if (strcmp(name, "tvdpi") == 0) {
+        if (out) out->density = ResTable_config::DENSITY_TV;
+        return true;
+    }
+    
     if (strcmp(name, "hdpi") == 0) {
         if (out) out->density = ResTable_config::DENSITY_HIGH;
         return true;