Preload zip before waiting for surface flinger

This saves about 200 msec by preloading media zip file before waiting
for surface flinger becomes ready.

Android Auto results:
BootAnimation: BootAnimationPreloadTiming start time: 8261ms
BootAnimation: BootAnimationPreloadStopTiming start time: 8508ms

Bug: 62056504

Test: adb logcat -s BootAnimation
Change-Id: Iaedf774983a66c2838452c45a04b3a1f4c728f17
diff --git a/cmds/bootanimation/bootanimation_main.cpp b/cmds/bootanimation/bootanimation_main.cpp
index a52a5e9..6c7b3e5 100644
--- a/cmds/bootanimation/bootanimation_main.cpp
+++ b/cmds/bootanimation/bootanimation_main.cpp
@@ -44,14 +44,16 @@
         sp<ProcessState> proc(ProcessState::self());
         ProcessState::self()->startThreadPool();
 
+        // create the boot animation object (may take up to 200ms for 2MB zip)
+        sp<BootAnimation> boot = new BootAnimation(audioplay::createAnimationCallbacks());
+
         waitForSurfaceFlinger();
 
-        // create the boot animation object
-        sp<BootAnimation> boot = new BootAnimation(audioplay::createAnimationCallbacks());
+        boot->run("BootAnimation", PRIORITY_DISPLAY);
+
         ALOGV("Boot animation set up. Joining pool.");
 
         IPCThreadState::self()->joinThreadPool();
     }
-    ALOGV("Boot animation exit");
     return 0;
 }