Remove unecessary exported symbols from libhwui.so

Test: compiles and links
Bug: 150782769
Change-Id: Ib49c1bf914b6bfaad1fb29371115df7c9eec08d2
diff --git a/libs/hwui/renderthread/RenderThread.h b/libs/hwui/renderthread/RenderThread.h
index 8be46a6..2c295bc 100644
--- a/libs/hwui/renderthread/RenderThread.h
+++ b/libs/hwui/renderthread/RenderThread.h
@@ -88,7 +88,7 @@
 
 public:
     // Sets a callback that fires before any RenderThread setup has occurred.
-    ANDROID_API static void setOnStartHook(JVMAttachHook onStartHook);
+    static void setOnStartHook(JVMAttachHook onStartHook);
     static JVMAttachHook getOnStartHook();
 
     WorkQueue& queue() { return ThreadBase::queue(); }