BufferedDataSource now caches redirects for subsequent requests on Android

BufferedDataSource now caches redirects for subsequent requests on Android

Previously BDS would always make requests to the initial URL. So if the
response was a redirect it would be followed on every subsequent request.
Now we save the destination after redirects and use it for future
 requests. This will speed up seeking because we need to do
fewer http requests, and is more robust because we can be more sure that
we're requesting bytes from the same resource each time. See the bug for
an example.

This is Android only for now because Android has historically had this
behavior. MultiBufferDataSource, which will replace BDS, also
implements this logic, so all platforms will soon have it.

BUG=606666
Review-Url: https://codereview.chromium.org/1924383002
Cr-Commit-Position: refs/heads/master@{#391121}
(cherry picked from commit 7ca0b0cfb005a022f08346a778b4481b985078c1)

Committed: https://chromium.googlesource.com/chromium/src/+/53716c01e23140c6889be4be1216245164f39728

[watk, 2016-05-03 20:05:41]

Description was changed from

==========
BufferedDataSource now caches redirects for subsequent requests on Android

Previously BDS would always make requests to the initial URL. So if the
response was a redirect it would be followed on every subsequent request.
Now we save the destination after redirects and use it for future
 requests. This will speed up seeking because we need to do
fewer http requests, and is more robust because we can be more sure that
we're requesting bytes from the same resource each time. See the bug for
an example.

This is Android only for now because Android has historically had this
behavior. MultiBufferDataSource, which will replace BDS, also
implements this logic, so all platforms will soon have it.

BUG=606666

Review-Url: https://codereview.chromium.org/1924383002
Cr-Commit-Position: refs/heads/master@{#391121}
(cherry picked from commit 7ca0b0cfb005a022f08346a778b4481b985078c1)
==========

to

==========
BufferedDataSource now caches redirects for subsequent requests on Android

Previously BDS would always make requests to the initial URL. So if the
response was a redirect it would be followed on every subsequent request.
Now we save the destination after redirects and use it for future
 requests. This will speed up seeking because we need to do
fewer http requests, and is more robust because we can be more sure that
we're requesting bytes from the same resource each time. See the bug for
an example.

This is Android only for now because Android has historically had this
behavior. MultiBufferDataSource, which will replace BDS, also
implements this logic, so all platforms will soon have it.

BUG=606666

Review-Url: https://codereview.chromium.org/1924383002
Cr-Commit-Position: refs/heads/master@{#391121}
(cherry picked from commit 7ca0b0cfb005a022f08346a778b4481b985078c1)

Committed:
https://chromium.googlesource.com/chromium/src/+/53716c01e23140c6889be4be1216...
==========

[watk, 2016-05-03 20:05:43]

Committed patchset #1 (id:1) manually as
53716c01e23140c6889be4be1216245164f39728.