`tests/wpt/css-tests/css-variables-1_dev/html/test_variable_legal_values.htm`
relies on setting `.data` on a text node inside a `<style>` element
to update a stylesheet, but this doesn’t work on Servo yet.
Add a copy of this file that uses a style attribute instead.
layout: Draw the insertion point in input elements.
Known issues:
* The caret doesn't show up if there's no text present, because we don't create text runs in that case. This should be a followup.
* Text runs don't support decomposing ligatures into their constituent subglyphs for advance computation, so the caret won't appear inside a ligature. This is a text run bug.
r? @mbrubeck
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Improve printing of DisplayLists
Use box tree characters to make DisplayLists easier to scan when
printing them out.
This is what the output looked like before:
```
#### start printing display list.
"####" Stacking context at Rect(800px×608px at (0px,0px)) with overflow Rect(800px×608px at (0px,0px)):
#### SolidColor(0,0,0,0). Rect(800px×608px at (0px,0px))
#### SolidColor(0,0,0,0). Rect(784px×0px at (8px,0px))
#### SolidColor(0,0.5019608,0,1). Rect(100px×100px at (0px,0px))
#### Child layers list length: 1
"########" Stacking context at Rect(100px×100px at (0px,0px)) with overflow Rect(100px×100px at (0px,0px)):
######## SolidColor(1,0,0,1). Rect(100px×100px at (0px,0px))
######## Child layers list length: 1
"############" Stacking context at Rect(100px×100px at (0px,0px)) with overflow Rect(100px×100px at (0px,0px)):
```
This is what it looks like after this patch:
```
┌ DisplayList
│ ├─ Layered StackingContext at Rect(800px×608px at (0px,0px)) with overflow Rect(800px×608px at (0px,0px)):
│ │ ├─ Block Backgrounds and Borders
│ │ │ ├─ SolidColor rgba(0, 0, 0, 0) @ Rect(800px×608px at (0px,0px)) (7f926f46f1f0)
│ │ │ └─ SolidColor rgba(0, 0, 0, 0) @ Rect(784px×0px at (8px,0px)) (7f926f46f2e0)
│ │ ├─ Layered StackingContext at Rect(100px×100px at (0px,0px)) with overflow Rect(100px×100px at (0px,0px)):
│ │ │ ├─ Backgrounds and Borders
│ │ │ │ └─ SolidColor rgba(1, 0, 0, 1) @ Rect(100px×100px at (0px,0px)) (7f926f46f310)
│ │ │ ├─ Layered StackingContext at Rect(100px×100px at (0px,0px)) with overflow Rect(100px×100px at (0px,0px)):
│ │ ├─ Layered StackingContext at Rect(100px×100px at (0px,0px)) with overflow Rect(100px×100px at (0px,0px)):
│ │ │ ├─ Backgrounds and Borders
│ │ │ │ └─ SolidColor rgba(0, 0.5019608, 0, 1) @ Rect(100px×100px at (0px,0px)) (7f926f46f3a0)
```
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Speedup mach startup
...by using a 'marker file' to indicate whether we actually need to run pip.
Also a minor tweak for clarity.
Before (consistently):
```
$ time ./mach >/dev/null
real 0m0.666s
user 0m0.477s
sys 0m0.190s
```
After:
```
$ time ./mach >/dev/null # first run
real 0m0.665s
user 0m0.501s
sys 0m0.166s
$ time ./mach >/dev/null
real 0m0.121s
user 0m0.083s
sys 0m0.039s
```
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