Make WebURLLoader capable of retaining received buffers.

In order to implement backpressure on resource loading, this CL
makes WebURLLoader capable of retaining received buffers. In the
current implementation, ResourceDispatcher takes care of the buffer
lifetime in OnReceivedData. With this CL, it passes a ReceivedData
object that contains payload, length and encoded_length. The difference
is that a ReceivedData object keeps payload valid while it is alive,
so we can store the buffer if we like (with care, of course).

This CL does not change the behavior, except one: it replaces a possible
use-after-free in ResourceDispatcher::OnReceivedData when using
|alternative_data| with |threaded_data_provider| with an incorrect
, but safe operation.

BUG=480746

Committed: https://crrev.com/65d393906dd7532c51bbb70c9c181eae3b1e1758
Cr-Commit-Position: refs/heads/master@{#332512}

Review URL: https://codereview.chromium.org/1103813002

Cr-Commit-Position: refs/heads/master@{#332554}

0 files changed, 0 insertions, 0 deletions