Revert "Auto merge of #18114 - emilio:revert-webgl-refactor, r=nox"

[nox]

This reverts commit 4d10d39, reversing
changes made to ee94e2b.

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This change is 

[highfive]

Heads up! This PR modifies the following files:

• @asajeffrey: components/constellation/pipeline.rs, components/constellation/lib.rs, components/constellation/Cargo.toml, components/constellation/constellation.rs
• @KiChjang: components/script/dom/webglframebuffer.rs, components/script/dom/webglshader.rs, components/script/dom/webgl_validations/tex_image_2d.rs, components/script/dom/htmlcanvaselement.rs, components/script/dom/window.rs and 24 more
• @fitzgen: components/script/dom/webglframebuffer.rs, components/script/dom/webglshader.rs, components/script/dom/webgl_validations/tex_image_2d.rs, components/script/dom/htmlcanvaselement.rs, components/script/dom/window.rs and 24 more
• @emilio: components/layout/display_list_builder.rs, components/script/dom/webglframebuffer.rs, components/script/dom/webglshader.rs, components/script/dom/webgl_validations/tex_image_2d.rs, components/layout/webrender_helpers.rs and 14 more

[highfive]

Warning

• These commits modify unsafe code. Please review it carefully!
• These commits modify gfx, layout, and script code, but no tests are modified. Please consider adding a test!

[nox]

@bors-servo r=emilio

[bors-servo]

📌 Commit 676f2c8 has been approved by emilio

[glennw]

@MortimerGoro Once this lands (and sticks) are you happy for me to remove all the webgl related code in WR?

[MortimerGoro]

@glennw Yes ;)

[bors-servo]

⌛ Testing commit 676f2c8 with merge c681d4e...

[bors-servo]

💔 Test failed - android

[jdm]

@bors-servo: retry

• #18116

[bors-servo]

⌛ Testing commit 676f2c8 with merge fbabcaf...

[bors-servo]

☀️ Test successful - android, arm32, arm64, linux-dev, linux-rel-css, linux-rel-wpt, mac-dev-unit, mac-rel-css1, mac-rel-css2, mac-rel-wpt1, mac-rel-wpt2, mac-rel-wpt3, mac-rel-wpt4, windows-msvc-dev
Approved by: emilio
Pushing fbabcaf to master...