Start using more typed units in the compositor

Now that rust-layers is starting to support typed units, we can use
them more thoroughly in the compositor. This is a step toward removing
as many untyped units as possible.
Remove RenderListener::set_layer_clip_rect

It is currently unused.
Support callback return types in codegen
Disable same-origin.html for intermittent failures (fixes #3180).

We don't currently implement the same-origin restriction at all, so there's
little point in running this test.
Merge pull request #3184 from Ms2ger/disable-workers-same-origin-test

Disable same-origin.html for intermittent failures (fixes #3180).; r=jgraham
Merge pull request #3183 from ChrisParis/callback-return

Support callback return types in codegen
Make text decorations be independent display items.

The goal it to avoid having too much layout logic (which gets more complex in vertical text) in gfx code.
Implement sideways text.
Merge pull request #3181 from SimonSapin/sideways-text

Sideways text
Rename AttrList to NamedNodeMap

This fixes issue #3135
Merge pull request #3179 from mrobinson/iframes

Remove RenderListener::set_layer_clip_rect
Merge pull request #3174 from Aaron1011/attrlist-namednodemap

Rename AttrList to NamedNodeMap
implement window.frames
Merge pull request #3186 from wenderen/Window.frames

implement window.frames; r=Manishearth
Share code between HTMLScriptElement:Text and Node:GetTextContent

Added a function in Node called collect_text_contents which is called
from both places.

Fixes #3157
Merge pull request #3189 from gilles-leblanc/issue-3157

Share code between HTMLScriptElement:Text and Node:GetTextContent; r=Manishearth
Disable ssl on android as openssl needs to be added to build system.
Merge pull request #3192 from glennw/disable-android-ssl

Disable ssl on android as openssl needs to be added to build system.
Revert "Add tests for the bit_struct! macro."

This reverts commit dd44a7d24affbef1841bf8aa4c8c0e9c3c4989f0.
Revert "fixup! Move PropertyBitField to a syntax extension."

This reverts commit 653f257029466fcc587d6ba17495a663cbd1693b.