Configure GC free to be 8MB for devices with >512MB RAM.

b/6606849

Change-Id: Idad46032b4b5d309db0319caeb7a1dfc0550f9f7
diff --git a/build/phone-hdpi-dalvik-heap.mk b/build/phone-hdpi-dalvik-heap.mk
index ab33b96..cc0ac90 100644
--- a/build/phone-hdpi-dalvik-heap.mk
+++ b/build/phone-hdpi-dalvik-heap.mk
@@ -18,4 +18,7 @@
 
 PRODUCT_PROPERTY_OVERRIDES += \
     dalvik.vm.heapstartsize=5m \
-    dalvik.vm.heapsize=32m
+    dalvik.vm.heapsize=32m \
+    dalvik.vm.heaptargetutilization=0.75 \
+    dalvik.vm.heapminfree=512k \
+    dalvik.vm.heapmaxfree=2m