There's proof-of-concept code now available for handling WebGL with GPU acceleration through Clutter's port of the WebKit engine. Due to limitations with Clutter, the WebGL support in WebKit as used by the GTK, Qt, and Mac OS X implementations isn't possible so a new design has been brewing.
Since the Clutter tool-kit doesn't expose direct OpenGL access, the existing WebGL implementations for WebKit won't work in Clutter's WebKit engine. As such, Collabora has been working on a new solution for doing WebGL.
This new solution adds a new mechanism to Clutter's Cogl (OpenGL back-end) component so that applications can now utilize OpenGL directly and draw into an offscreen frame-buffer and then composite that back into Clutter. This Cogl work could potentially be of more use than just this WebKit-WebGL work.
Right now this work is just considered proof-of-concept and that more work must take place before this is ready to be merged upstream so that Clutter's WebKit can finally tap WebGL.
More details can be found in this blog post
by Tomeu Vizoso, including a brief demo video of Clutter WebGL in action.