Ability to Extract DevTools Frame ID from cef_frame_t

[aleitner]

I'm facing a challenge with handling iframe load errors in CEF. Specifically, the on_load_error callback effectively handles main frame errors, allowing for custom error pages. However, this approach falls short with iframes due to the inability to determine which child frame details map to the failing iframe from the getFrameTree DevTools command, as recommended by community guidelines.

When an iframe fails to load (e.g., due to a bad URL), I cannot target it specifically for custom error handling without affecting other frames.

I propose enhancing CEF to allow direct mapping or extraction of the DevTools frame ID from cef_frame_t. This feature would enable precise error handling for iframes, including the display of custom error pages within the affected iframe only.

[magreenblatt]

The last time I looked at this it wasn't possible to get DevTools IDs unless DevTools was already loaded/running. Just something to keep in mind.