Set a maximum virtual display size

This device can only support virtual displays up to 2048 pixels on a
side. The variable set in this change is observed in SurfaceFlinger,
which will bypass the hardware composer for any virtual displays
larger than this.

Bug: 17701816
Change-Id: Ia02bd5c88b6c1b3b0c383d7a23e93a22068ce7da
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 26d5588..a60840b 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -42,6 +42,10 @@
 # of the device.
 MAX_EGL_CACHE_SIZE := 2048*1024
 
+# Maximum dimension (width or height) of a virtual display that will be
+# handled by the hardware composer
+MAX_VIRTUAL_DISPLAY_DIMENSION := 2048
+
 BOARD_EGL_CFG := device/moto/shamu/egl.cfg
 
 BOARD_USES_ALSA_AUDIO := true