Add RenderFrameHostDelegate and plumb it through all the necessary classes.

Add RenderFrameHostDelegate and plumb it through all the necessary classes.

This is an empty interface for now. I'm doing this separately in preparation for moving plugin creation from RenderView to RenderFrame.

BUG=245126
R=creis@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=238709

[Charlie Reis, 2013-12-04 16:23:46]

Yep, I imagine we'll need this soon enough.  LGTM.

[nasko, 2013-12-04 16:42:15]

Drive-by comment:
Do we want RenderFrameHostDelegate to go all the way up to WebContentsImpl?
I think it will be better to delegate up to the FrameTree and then the FrameTree
can delegate to its embedder. This way anyone trying to display a page (for
example interstitials) doesn't need to know directly about RFH, just creates a
FrameTree and Navigator. It will match today's world of RenderViewHost - you
embed a page level concept, not the underpinnings of it.

[jam, 2013-12-04 17:35:06]

On 2013/12/04 16:42:15, nasko wrote:
> Drive-by comment:
> Do we want RenderFrameHostDelegate to go all the way up to WebContentsImpl?

The reason I thought it should go all the way is because there are going to be a
lot of WebContentsObserver callbacks that are kicked off by RenderFrameHost.
Already it'll be cumbersome that each time we add/change a callback we'll have
to touch RFHImpl, RFHD and WCImpl.

> I think it will be better to delegate up to the FrameTree and then the
FrameTree
> can delegate to its embedder. This way anyone trying to display a page (for
> example interstitials)

Note, other than interstitials, the only way to display a page is through
WebContents. A long time ago we had lots of places in chrome that would use
RenderViewHost, but they were all switched to WC. If there was a way to change
interstitials to use WC swapping, that'd be even better but I don't know how
feasible it is. Regardless, I lean towards making interstitial code know about
RFHD rather than addding another 4 files to change each time we need to plumb
something from RFH to WC.

> doesn't need to know directly about RFH, just creates a
> FrameTree and Navigator. It will match today's world of RenderViewHost - you
> embed a page level concept, not the underpinnings of it.