This allows to cleanup resources earlier if they stop being used. Right
now all resources were cleaned up when the context was destroyed, this is
a slightly better approach.
We ignore the possible failure of the send() call, since we don't keep
track of these resources from the `WebGLRenderingContext` structure, so
a texture could be destroyed after the context and give us problems.
To actually make the multiprocess communication work, we'll need to
reroute the task creation to the pipeline or the compositor. But this
works as a first step.
This improves the encapsulation and consistency in our WebGL
implementation.
Also allows to implement new methods such as `getShaderSource()`.
It will also allow us to use `delete()` in the destructors of them (note
that we will want to keep track of them from the context).
This commit implements:
* WebGLFramebuffer
* WebGLRenderbuffer
* WebGLTexture
And adds the following methods to `WebGLRenderingContext`:
* create{Texture,Framebuffer,Renderbuffer}
* bind{Texture,Framebuffer,Renderbuffer}
* destroy{Buffer,Texture,Framebuffer,Renderbuffer}
Fixes:
* WebGLUniform location shouldn't inherit from WebGLObject.
Known Issues:
* WebGL objects have to be destroyed on drop, we may want to keep a reference to the context, or maybe a clone of the renderer to achieve this
Also refactors a huge part of the current implementation, to allow
failing on creation of different WebGL objects.
Blocked on https://github.com/servo/gleam/pull/22
A reftest for most of the added functionality is not doable right now,
we need a few more functions in order to upload a texture, for example.
