private long getLastAppUpdateTime() {
            try {
                return mContext.getPackageManager()
                        .getPackageInfo(mContext.getPackageName(), 0).lastUpdateTime;
            } catch (PackageManager.NameNotFoundException e) {
                // Should not happen
                throw new RuntimeException(e);
            }
        }
Cancels the execution. The callback passed into {@link #execute} won't be called, and
the references to it will be released.
customtabs/src/android/support/customtabs/trusted/splashscreens/SplashImageTransferTask.java