[automated] Drop needless <vector> includes in /components/download/public/common

This is among the most costful includes for the Chromium build.
https://commondatastorage.googleapis.com/chromium-browser-clang/include-analysis.html

This batch of CLs attempts to detect and remove leftover includes with a
heuristic: choose files which don't contain 'std::vector' or 'push_back'.
This doesn't really guarantee that std::vector is not being used, as
shown by the snippets below, so please review carefully.
```
auto v = GetVector();
MyVectorAlias v = GetVector();
my_vector_ = GetVector();
```

This CL was uploaded by git cl split.

R=shaktisahu@chromium.org

Bug: 1233968
Change-Id: I3783a2acb0806e1775e2668e27a5a9bf48d4ca66
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3058248


Auto-Submit: Victor Vianna <victorvianna@google.com>
Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Commit-Queue: Victor Vianna <victorvianna@google.com>
Cr-Commit-Position: refs/heads/master@{#910213}