Enable file path watcher for Android

base/files/file_path_watcher_linux.cc

Index: base/files/file_path_watcher_linux.cc
diff --git a/base/files/file_path_watcher_linux.cc b/base/files/file_path_watcher_linux.cc
index 205a3eb779fbff1127a5c71657d86fa05130447a..d77b0392fc5c7999b9c6f94c22824a2834447859 100644
--- a/base/files/file_path_watcher_linux.cc
+++ b/base/files/file_path_watcher_linux.cc
@@ -373,10 +373,10 @@ bool FilePathWatcherImpl::Watch(const FilePath& path,
   std::vector<FilePath::StringType> comps;
   target_.GetComponents(&comps);
   DCHECK(!comps.empty());
-  for (std::vector<FilePath::StringType>::const_iterator comp(++comps.begin());

[jar (doing other things), 2012/08/30 02:47:25]

I didn't especially like this pre-increment on the return from begin(), but it
wasn't clear why the new code was different.

Can you point out the change here?  ...was it just to make a compiler happy??

[yongsheng, 2012/08/30 04:50:17]

yes, see the compiler error on Android.

-       comp != comps.end(); ++comp) {
+  std::vector<FilePath::StringType>::const_iterator comp = comps.begin();

[Mark Mentovai, 2012/08/30 02:50:42]

Why are you changing this?

[yongsheng, 2012/08/30 03:06:30]

The fix for file_path_watcher_linux.cc is because of the below error on Android:
base/files/file_path_watcher_linux.cc:376:77: error: lvalue required as
increment operand.
comps.begin() returns a rvalue.

+  for (++comp; comp != comps.end(); ++comp)
     watches_.push_back(WatchEntry(InotifyReader::kInvalidWatch, *comp));
-  }
+
   watches_.push_back(WatchEntry(InotifyReader::kInvalidWatch,
                                 FilePath::StringType()));
   return UpdateWatches();