Auto merge of #25622 - pylbrecht:composite.op.clear, r=jdm

Add missing CanvasRenderingContext2D global composition operation "clear"

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix part of #25331

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- [x] There are tests for these changes

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components/canvas/raqote_backend.rs

@@ -1002,6 +1002,7 @@ impl ToRaqoteStyle for CompositionStyle {
             CompositionStyle::Copy => raqote::BlendMode::Src,
             CompositionStyle::Lighter => raqote::BlendMode::Add,
             CompositionStyle::Xor => raqote::BlendMode::Xor,
+            CompositionStyle::Clear => raqote::BlendMode::Clear,
         }
     }
 }

components/canvas_traits/canvas.rs

@@ -254,6 +254,7 @@ pub enum CompositionStyle {
     Copy,
     Lighter,
     Xor,
+    Clear,
 }
 
 impl FromStr for CompositionStyle {
@@ -272,6 +273,7 @@ impl FromStr for CompositionStyle {
             "copy" => Ok(CompositionStyle::Copy),
             "lighter" => Ok(CompositionStyle::Lighter),
             "xor" => Ok(CompositionStyle::Xor),
+            "clear" => Ok(CompositionStyle::Clear),
             _ => Err(()),
         }
     }
@@ -291,6 +293,7 @@ impl CompositionStyle {
             CompositionStyle::Copy => "copy",
             CompositionStyle::Lighter => "lighter",
             CompositionStyle::Xor => "xor",
+            CompositionStyle::Clear => "clear",
         }
     }
 }

tests/wpt/metadata/2dcontext/compositing/2d.composite.operation.clear.html.ini

@@ -1,5 +0,0 @@
-[2d.composite.operation.clear.html]
-  type: testharness
-  [Canvas test: 2d.composite.operation.clear]
-    expected: FAIL
-

tests/wpt/metadata/offscreen-canvas/compositing/2d.composite.operation.clear.html.ini

@@ -1,4 +0,0 @@
-[2d.composite.operation.clear.html]
-  [OffscreenCanvas test: 2d.composite.operation.clear]
-    expected: FAIL
-

tests/wpt/metadata/offscreen-canvas/compositing/2d.composite.operation.clear.worker.js.ini

@@ -1,4 +0,0 @@
-[2d.composite.operation.clear.worker.html]
-  [2d]
-    expected: FAIL
-