Set the default accept header for main resources in RenderFrame

Set the default accept header for main resources in RenderFrame

Currently it is set in blink in FrameFetchContext::addAdditionalRequestHeaders.
This CL moves it to RenderFrameImpl::willSendRequest.

BUG=376025
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=275241

[clamy, 2014-06-05 14:01:40]

@ppi: PTAL

[ppi, 2014-06-05 15:10:10]

Thanks, one question below.

https://codereview.chromium.org/313313002/diff/20001/content/renderer/render_...
File content/renderer/render_frame_impl.cc (right):

https://codereview.chromium.org/313313002/diff/20001/content/renderer/render_...
content/renderer/render_frame_impl.cc:2413: // already.
In which circumstances it will be already set?

[clamy, 2014-06-05 15:22:01]

https://chromiumcodereview.appspot.com/313313002/diff/20001/content/renderer/...
File content/renderer/render_frame_impl.cc (right):

https://chromiumcodereview.appspot.com/313313002/diff/20001/content/renderer/...
content/renderer/render_frame_impl.cc:2413: // already.
On 2014/06/05 15:10:10, ppi wrote:
> In which circumstances it will be already set?

This function is also called on redirects. If the header has been modified after
the default header has been set (which I think is unlikely, but for example
devtools can write special headers), then on a redirect the modification would
be overwritten.

[ppi, 2014-06-05 16:09:09]

lgtm, thanks!

[clamy, 2014-06-05 16:14:40]

@jam: PTAL

@ppi: thanks!

[clamy, 2014-06-05 16:15:22]

@jam: PTAL

[jam, 2014-06-05 19:07:22]

lgtm

[clamy, 2014-06-05 19:43:27]

The CQ bit was checked by clamy@chromium.org

[commit-bot: I haz the power, 2014-06-05 19:45:36]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/clamy@chromium.org/313313002/20001

[commit-bot: I haz the power, 2014-06-05 21:14:10]

Change committed as 275241