Use only one GL context per process, share chaches.

Change-Id: Ieabaa25338d2f4b8d4fd90e7401ad6e7452eae11
diff --git a/libs/hwui/PatchCache.h b/libs/hwui/PatchCache.h
index de95087..e874a16 100644
--- a/libs/hwui/PatchCache.h
+++ b/libs/hwui/PatchCache.h
@@ -43,6 +43,7 @@
 
 class PatchCache: public OnEntryRemoved<PatchDescription, Patch*> {
 public:
+    PatchCache();
     PatchCache(uint32_t maxCapacity);
     ~PatchCache();