It's not a full IDE, but the WebGL inspector browser extension by benvanik seems promising:
http://benvanik.github.com/WebGL-Inspector/
From his page a number of features that might be along the lines you're looking for:
- Extension for injecting into pages
- Embed in an existing application with a single script include
- Capture entire GL frames
- Annotated call log with stepping/resource navigation and redundant call warnings
- Pixel history see all draw calls that contributed to a pixel + blending information
- GL state display
- Resource browsers for textures, buffers, and programs
I've only used it a little bit, but it seems to be a lot better than working in the bare browser.
