fix: render process crash handling

[samuelmaddock]

Description of Change

#34411 didn't have a repro case by the time of merging. This PR includes a test which reproduced the crash prior to the fix.

Additionally, another crash was found while testing same-origin crash recovery. That fix is included as well.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixed a crash when loading a same-origin URL after a render process crash.

[samuelmaddock]

Tests failing due to DCHECK() added in #34411, investigating now.

[samuelmaddock]

The DCHECK(render_frame_) case was being hit from here:

electron/shell/browser/api/electron_api_web_contents.cc

Lines 1506 to 1508 in eb26f99

	auto* web_frame = WebFrameMain::FromRenderFrameHost(render_frame_host);
	if (web_frame)
	web_frame->MaybeSetupMojoConnection();

This occurs when the RFH has crashed and a new one is setup for same-origin navigation while the existing WebFrameMain reference is kept alive.

First RenderFrameCreated is called with the newly created RFH. It looks up the corresponding WebFrameMain instance by the FrameTreeNode ID. It exists, but remains in a disposed state due to the old RFH being killed by a crash.

electron/shell/browser/api/electron_api_web_contents.cc

Lines 1520 to 1522 in eb26f99

	void WebContents::RenderFrameCreated(
	content::RenderFrameHost* render_frame_host) {
	HandleNewRenderFrame(render_frame_host);

Then RenderFrameHostChanged is called which will swap the RFH referenced by the WebFrameMain instance. Finally it will setup the mojo connection.

electron/shell/browser/api/electron_api_web_contents.cc

Lines 1572 to 1585 in eb26f99

	void WebContents::RenderFrameHostChanged(content::RenderFrameHost* old_host,
	content::RenderFrameHost* new_host) {
	// During cross-origin navigation, a FrameTreeNode will swap out its RFH.
	// If an instance of WebFrameMain exists, it will need to have its RFH
	// swapped as well.
	//
	// |old_host| can be a nullptr so we use |new_host| for looking up the
	// WebFrameMain instance.
	auto* web_frame =
	WebFrameMain::FromFrameTreeNodeId(new_host->GetFrameTreeNodeId());
	if (web_frame) {
	web_frame->UpdateRenderFrameHost(new_host);
	}
	}

[release-clerk]

Release Notes Persisted

Fixed a crash when loading a same-origin URL after a render process crash.

[trop]

I have automatically backported this PR to "18-x-y", please check out #34430

[trop]

I have automatically backported this PR to "19-x-y", please check out #34431

[trop]

I have automatically backported this PR to "20-x-y", please check out #34432