Another recently announced option might be useful one day is
Ultralight. Some
discussion on HackerNews. Developed by the author of Awesomium.
Not suitable for your case yet though. Windows & Mac only, GPU required, commercial and closed-source.
We started over with WebKit, stripped it to the bare-minimum, then rebuilt it from scratch with an eye towards embedding. The result is a fast, lightweight, low-memory HTML UI solution that blends the power of Chromium with the small footprint of Native UI.
Awesomium was similar in scope to CEF (and actually predates it by many months), it's goal was to wrap Chromium and make it accessible via a pixel buffer instead of a platform window.
Chromium in its initial stages was very tight and focused in its scope and only supported a subset of the current web platform we see today, I think the first Awesomium DLLs were something like 18MB or less.
Over the years Chromium grew larger and accumulated more complexity to a point where it was no longer a web renderer but something closer to an OS platform. Many of the features added were somewhat irrelevant for users looking to render HTML as a frontend but downstream developers like Awesomium and CEF had no choice but to integrate their updates as a whole since we were de-facto wrappers.
Ultralight is different. It's a hard fork of WebKit and has a considerable number of differences tuned specifically for embedders (such as the Platform API and virtual GPUDriver). We have much more control over the project and will continue making design decisions that benefit embedding as a first-class use-case.
Reasons to use Ultralight over EAWebKit are ease of use, pure GPU rendering and performance (EAWebKit, last I checked, depends on Cairo for all its rendering), and the backing of an actual commercial company that will support and maintain the product for years to come.