Based on [ebalint](https://github.com/ebalint)'s original patch, this commit implements the linear and radial gradients for the canvas. The PR also includes test cases.
Depends on #4623 and servo/rust-azure#136.
Implements view-source protocol by having a view-source handler, and modifying the content type to be text/plain if that is used.
Implements text/plain handling. This allows view-source content to display as plain text.
Example usage:
./mach run http://cd.pn/x.txt
./mach run view-source:http://tinyvid.tv/
This fixes issue #4181. Issue #3649 includes "support text/plain" so this possibly fixes some of that issue as well.
@jdm This initial version has a few outstanding issues that I wanted to invite input on. Specifically:
1. I had some difficulty finding a home for the `StorageType` enum. Structs defined outside of the `script` module don't seem to be able to use the `#[jstraceable]` annotation and the `net` module (where `StorageTask` lives) doesn't have access to `script`. Per Simon Sapin's suggestion, I worked around this temporarily by creating a `TraceableStorageType` stand-in struct that was traceable and which could be translated into a regular `StorageType` when being sent to the `StorageTask`. Unsure of the best way to resolve this hack. Thoughts?
2. Apart from the `Storage` constructor used in `Window::SessionStorage` and the new `Window::LocalStorage`, there's also a method called `Storage::Constructor`. I'm unclear on what (if anything) will actually invoke this, so I'm not sure which variant of `StorageType` to use here. I've temporarily created an `Unknown` variant of `StorageType` as a placeholder.
3. I discovered that the web platform tests directory's localStorage tests. Many of them now pass despite the configured expectation that they fail. However, several do not pass. Is there a good way for me to add debug logging or otherwise get a sense of which assertion failed / what went wrong?
Thanks for your continued help!
This patch enables the use of `arc()` on the canvas.
I couldn't add reftest this time, as it involves some antialiasing issues, and so the reference doesn't match.
