Doing performance work with GPUs is harder than with CPUs because of the asynchronous and massively parallel architecture.
PIX - Can do timing of Direct3D calls. Works reasonably well with Firefox. See also Debugging With PIX.
NVIDIA PerfHUD - Last I checked required a special build to be used.
NVIDIA Parallel Nsight - Haven't tried.
AMD GPU ShaderAnalyzer - Will compile a shader and show the machine code and give static pipeline estimations. Not that useful for Firefox because all of our shaders are pretty simple.
AMD GPU PerfStudio - I had trouble getting this to work, and can't remember whether I actually did or not.
Intel Graphics Performance Analyzers - Haven't tried.
APITrace - Open source, works OK.
PVRTrace - Doesn't seem to emit traces on android/Nexus S. Looks like it's designed for X11-based linux-ARM devices, OMAP3 is mentioned a lot in the docs ...
Accurately Profiling Direct3D API Calls (Direct3D 9)- Suggests avoiding normal profilers like xperf and instead measuring the time to flush the command buffer.
OS X - Best Practices for Working with Texture Data - Sort of old, but still useful.