two plots sharing x-axis with different geoms in ggplot2

Question

I'd like plots that share a horizontal axis, but with different vertical axes. This would be easy using facet_grid if I wanted them to use the same geom, but they have different geoms.

The best I have so far to above facet_grid a bit:

library(gridExtra)
library(reshape2)

n = 10
df <- data.frame(X = seq.int(n), 
                 Count = sample(1:50, size=n), 
                 Y = sample(1:10000000, size=n))

long <- melt(df, id="X")
long$Y <- with(long, ifelse(variable=="Y", value, NA))
long$Count <- with(long, ifelse(variable=="Count", value, NA))
long$variable <- factor(long$variable, levels = c("Y", "Count"))

ggplot(long) + 
  geom_point(aes(x=X, y=Y)) +
  geom_bar(aes(x=X,y=Count), stat="identity") +
  facet_grid(variable ~ ., scales="free_y") +
  ylab("")

Prior to that, I was doing this (which can get the axis alignment wrong and is in general very fragile):

pointsPlot <- ggplot(df) + geom_point(aes(x=X, y=Y))
barPlot <-  ggplot(df) + geom_bar(aes(x=X, y=Count), stat="identity")
grid.arrange(pointsPlot, barPlot, ncol=1)

Does anyone have less hacky way to suggest?