Auto merge of #12741 - changm:shader, r=ConnorGBrewster

update servo to use webrender shaders

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Pulls shaders from webrender and update the webrender commit.
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- [X ] `./mach build -d` does not report any errors
- [ X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [X ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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resources/shaders/ps_angle_gradient.fs.glsl

@@ -21,7 +21,7 @@ void main(void) {
     float sa = sin(angle);
     float ca = cos(angle);
 
-	float sx = vStartPoint.x * ca - vStartPoint.y * sa;
+    float sx = vStartPoint.x * ca - vStartPoint.y * sa;
     float ex = vEndPoint.x * ca - vEndPoint.y * sa;
     float d = ex - sx;
 

resources/shaders/ps_border.fs.glsl

@@ -28,7 +28,7 @@ vec4 draw_dotted_edge() {
   // like firefox.
   float circleSpacing = diameter * 2.2;
 
-  vec2 size = vec2(vBorders.z, vBorders.w);
+  vec2 size = vBorders.zw;
   // Get our position within this specific segment
   vec2 position = vDevicePos - vBorders.xy;
 
@@ -68,15 +68,16 @@ vec2 get_dashed_nudge_factor(vec2 dash_size, bool is_corner) {
   bool xAxisFudge = vBorders.z > vBorders.w;
   if (xAxisFudge) {
     return vec2(dash_size.x / 2.0, 0);
-  } else {
-    return vec2(0.0, dash_size.y / 2.0);
   }
+
+  return vec2(0.0, dash_size.y / 2.0);
 }
 
 vec4 draw_dashed_edge(bool is_corner) {
   // Everything here should be in device pixels.
   // We want the dot to be roughly the size of the whole border spacing
   // 5.5 here isn't a magic number, it's just what mostly looks like FF/Chrome
+  // TODO: Investigate exactly what FF does.
   float dash_interval = min(vBorders.w, vBorders.z) * 5.5;
   vec2 edge_size = vec2(vBorders.z, vBorders.w);
   vec2 dash_size = vec2(dash_interval / 2.0, dash_interval / 2.0);
@@ -143,6 +144,8 @@ void draw_dashed_border(void) {
   }
 }
 
+// TODO: Investigate performance of this shader and see
+//       if it's worthwhile splitting it / removing branches etc.
 void main(void) {
 	if (vRadii.x > 0.0 &&
 		(distance(vRefPoint, vLocalPos) > vRadii.x ||
@@ -178,7 +181,6 @@ void main(void) {
     default:
     {
       discard;
-      break;
     }
   }
 }

resources/shaders/ps_border.vs.glsl

@@ -107,7 +107,5 @@ void main(void) {
     vDevicePos = vi.global_clamped_pos;
 
     // These are in device space
-    vBorders = vec4(border.info.local_rect.x, border.info.local_rect.y,
-                    border.info.local_rect.z,
-                    border.info.local_rect.w) * uDevicePixelRatio;
+    vBorders = border.info.local_rect * uDevicePixelRatio;
 }

resources/shaders/ps_box_shadow.vs.glsl

@@ -4,8 +4,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 struct BoxShadow {
-	PrimitiveInfo info;
-	vec4 color;
+    PrimitiveInfo info;
+    vec4 color;
     vec4 border_radii_blur_radius_inverted;
     vec4 bs_rect;
     vec4 src_rect;

resources/shaders/ps_gradient.vs.glsl

@@ -7,7 +7,7 @@
 #define DIR_VERTICAL        uint(1)
 
 struct Gradient {
-	PrimitiveInfo info;
+    PrimitiveInfo info;
     vec4 color0;
     vec4 color1;
     uvec4 dir;

resources/shaders/shared.glsl

@@ -9,11 +9,11 @@
     #define varying out
 
     // Uniform inputs
-	uniform mat4 uTransform;       // Orthographic projection
-  uniform float uDevicePixelRatio;
+    uniform mat4 uTransform;       // Orthographic projection
+    uniform float uDevicePixelRatio;
 
     // Attribute inputs
-	in vec3 aPosition;
+    in vec3 aPosition;
 #endif
 
 //======================================================================================

resources/shaders/shared_other.glsl

@@ -11,8 +11,8 @@
 
     // box-shadow
     in vec4 aBorderPosition;
-	in vec4 aBorderRadii;
-	in float aBlurRadius;
+    in vec4 aBorderRadii;
+    in float aBlurRadius;
 
     // blur
     in vec2 aDestTextureSize;