Copy shaders from WR repo.

resources/shaders/ps_angle_gradient.vs.glsl

@@ -0,0 +1,38 @@
+#line 1
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+struct AngleGradient {
+	PrimitiveInfo info;
+    vec4 start_end_point;
+    uvec4 stop_count;
+    vec4 colors[MAX_STOPS_PER_ANGLE_GRADIENT];
+    vec4 offsets[MAX_STOPS_PER_ANGLE_GRADIENT/4];
+};
+
+layout(std140) uniform Items {
+    AngleGradient gradients[WR_MAX_PRIM_ITEMS];
+};
+
+void main(void) {
+    AngleGradient gradient = gradients[gl_InstanceID];
+    VertexInfo vi = write_vertex(gradient.info);
+
+    vStopCount = int(gradient.stop_count.x);
+    vPos = vi.local_clamped_pos;
+
+    // Snap the start/end points to device pixel units.
+    // I'm not sure this is entirely correct, but the
+    // old render path does this, and it is needed to
+    // make the angle gradient ref tests pass. It might
+    // be better to fix this higher up in DL construction
+    // and not snap here?
+    vStartPoint = floor(0.5 + gradient.start_end_point.xy * uDevicePixelRatio) / uDevicePixelRatio;
+    vEndPoint = floor(0.5 + gradient.start_end_point.zw * uDevicePixelRatio) / uDevicePixelRatio;
+
+    for (int i=0 ; i < int(gradient.stop_count.x) ; ++i) {
+        vColors[i] = gradient.colors[i];
+        vOffsets[i] = gradient.offsets[i];
+    }
+}