Check clock accuracy before attempting to display clock

The RTC may not be set yet, may have been reset, or may have drifted
significantly if the device time hasn't been updated in a long time.

Using the the last_time_change file to determine if the time is known to
be accurate and only display the clock when that is the case.

Bug: 27802041
Change-Id: I845cf9c74fcb4009504f1bab853e04146fa19e1d
diff --git a/cmds/bootanimation/BootAnimation.h b/cmds/bootanimation/BootAnimation.h
index d49e1ec..1c3d53a 100644
--- a/cmds/bootanimation/BootAnimation.h
+++ b/cmds/bootanimation/BootAnimation.h
@@ -51,6 +51,24 @@
     virtual void        onFirstRef();
     virtual void        binderDied(const wp<IBinder>& who);
 
+    bool                updateIsTimeAccurate();
+
+    class TimeCheckThread : public Thread {
+    public:
+        TimeCheckThread(BootAnimation* bootAnimation);
+        virtual ~TimeCheckThread();
+    private:
+        virtual status_t    readyToRun();
+        virtual bool        threadLoop();
+        bool                doThreadLoop();
+        void                addTimeDirWatch();
+
+        int mInotifyFd;
+        int mSystemWd;
+        int mTimeWd;
+        BootAnimation* mBootAnimation;
+    };
+
     struct Texture {
         GLint   w;
         GLint   h;
@@ -113,8 +131,10 @@
     sp<SurfaceControl> mFlingerSurfaceControl;
     sp<Surface> mFlingerSurface;
     bool        mClockEnabled;
+    bool        mTimeIsAccurate;
     String8     mZipFileName;
     SortedVector<String8> mLoadedFiles;
+    sp<TimeCheckThread> mTimeCheckThread;
 };
 
 // ---------------------------------------------------------------------------