--- a/dom/canvas/test/webgl-conf/checkout/conformance/glsl/misc/00_test_list.txt
+++ b/dom/canvas/test/webgl-conf/checkout/conformance/glsl/misc/00_test_list.txt
@@ -31,17 +31,17 @@ shader-with-arbitrary-indexing.vert.html
 --min-version 1.0.2 shader-with-array-of-structs-uniform.html
 shader-with-attrib-array.vert.html
 shader-with-attrib-struct.vert.html
 shader-with-clipvertex.vert.html
 --min-version 1.0.2 shader-with-conditional-scoping.html
 --min-version 1.0.2 shader-with-conditional-scoping-negative.html
 shader-with-default-precision.frag.html
 shader-with-default-precision.vert.html
-shader-with-define-line-continuation.frag.html
+--max-version 1.9.9 shader-with-define-line-continuation.frag.html
 shader-with-dfdx-no-ext.frag.html
 shader-with-dfdx.frag.html
 --min-version 1.0.2 shader-with-do-loop.html
 shader-with-error-directive.html
 shader-with-explicit-int-cast.vert.html
 shader-with-float-return-value.frag.html
 --min-version 1.0.2 shader-with-for-scoping.html
 --min-version 1.0.2 shader-with-for-loop.html

--- a/dom/canvas/test/webgl-conf/checkout/conformance/misc/invalid-passed-params.html
+++ b/dom/canvas/test/webgl-conf/checkout/conformance/misc/invalid-passed-params.html
@@ -39,16 +39,17 @@
 <div id="console"></div>
 
 <script>
 "use strict";
 description("Test for invalid passed parameters");
 
 var wtu = WebGLTestUtils;
 var context = wtu.create3DContext();
+var contextVersion = wtu.getDefault3DContextVersion();
 
 debug("");
 debug("Test createShader()");
 wtu.shouldGenerateGLError(context, context.NO_ERROR, "context.createShader(context.FRAGMENT_SHADER)");
 wtu.shouldGenerateGLError(context, context.NO_ERROR, "context.createShader(context.VERTEX_SHADER)");
 wtu.shouldGenerateGLError(context, context.INVALID_ENUM, "context.createShader(0)");
 wtu.shouldGenerateGLError(context, context.INVALID_ENUM, "context.createShader(context.TRIANGLES)");
 
@@ -105,17 +106,17 @@ function generateShaderSource(opt_invali
   }
   if (opt_invalidCommentChar != undefined) {
     invalidCommentString += opt_invalidCommentChar;
   }
   return "uniform float " + validUniformName + invalidIdentifierString + ";\n"
                           + "varying float " + validAttribName + ";\n"
                           + "void main() {\n"
                           + validAttribName  + " = " + validUniformName + ";\n"
-                          + "gl_Position = vec4(0.0, 0.0, 0.0, 1.0); }\n";
+                          + "gl_Position = vec4(0.0, 0.0, 0.0, 1.0); }\n"
                           + "//.+-/*%<>[](){}^|&~=!:;,?# " + invalidCommentString;
 }
 var vShader = context.createShader(context.VERTEX_SHADER);
 context.shaderSource(vShader, generateShaderSource());
 context.compileShader(vShader);
 shouldBe("context.getError()", "context.NO_ERROR");
 var fShader = context.createShader(context.FRAGMENT_SHADER);
 context.shaderSource(fShader, "precision mediump float;\n"
@@ -138,16 +139,19 @@ shouldBe("context.getError()", "context.
 context.getAttribLocation(program, validAttribName);
 shouldBe("context.getError()", "context.NO_ERROR");
 context.getUniformLocation(program, validUniformName);
 shouldBe("context.getError()", "context.NO_ERROR");
 
 debug("");
 debug("Test shaderSource() with invalid characters");
 for (var i = 0; i < invalidSet.length; ++i) {
+  // Backslash as line-continuation is allowed in WebGL 2.0.
+  if (contextVersion > 1 && invalidSet[i] == '\\')
+    continue;
   var validShaderSource = generateShaderSource(undefined, invalidSet[i]);
   context.shaderSource(vShader, validShaderSource);
   shouldBe("context.getError()", "context.NO_ERROR");
   var invalidShaderSource = generateShaderSource(invalidSet[i], undefined);
   context.shaderSource(vShader, invalidShaderSource);
   shouldBe("context.getError()", "context.INVALID_VALUE");
 }
 

--- a/dom/canvas/test/webgl-conf/generated-mochitest.ini
+++ b/dom/canvas/test/webgl-conf/generated-mochitest.ini
@@ -5097,18 +5097,16 @@ skip-if = (os == 'android' || os == 'lin
 [generated/test_2_conformance__glsl__misc__shader-with-conditional-scoping-negative.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-conditional-scoping.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-default-precision.frag.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-default-precision.vert.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
-[generated/test_2_conformance__glsl__misc__shader-with-define-line-continuation.frag.html]
-skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-dfdx-no-ext.frag.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-dfdx.frag.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-do-loop.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))
 [generated/test_2_conformance__glsl__misc__shader-with-error-directive.html]
 skip-if = (os == 'android' || os == 'linux' || (os == 'win' && os_version == '5.1'))