--- a/dom/canvas/WebGLContextGL.cpp
+++ b/dom/canvas/WebGLContextGL.cpp
@@ -807,16 +807,17 @@ WebGLContext::GetRenderbufferParameter(G
     if (!mBoundRenderbuffer) {
         ErrorInvalidOperation("getRenderbufferParameter: no render buffer is bound");
         return JS::NullValue();
     }
 
     MakeContextCurrent();
 
     switch (pname) {
+        case LOCAL_GL_RENDERBUFFER_SAMPLES:
         case LOCAL_GL_RENDERBUFFER_WIDTH:
         case LOCAL_GL_RENDERBUFFER_HEIGHT:
         case LOCAL_GL_RENDERBUFFER_RED_SIZE:
         case LOCAL_GL_RENDERBUFFER_GREEN_SIZE:
         case LOCAL_GL_RENDERBUFFER_BLUE_SIZE:
         case LOCAL_GL_RENDERBUFFER_ALPHA_SIZE:
         case LOCAL_GL_RENDERBUFFER_DEPTH_SIZE:
         case LOCAL_GL_RENDERBUFFER_STENCIL_SIZE:

--- a/dom/canvas/WebGLRenderbuffer.cpp
+++ b/dom/canvas/WebGLRenderbuffer.cpp
@@ -253,16 +253,17 @@ WebGLRenderbuffer::GetRenderbufferParame
         if (!mFormat)
             return 0;
 
         if (!mFormat->format->hasStencil)
             return 0;
 
         return 8;
 
+    case LOCAL_GL_RENDERBUFFER_SAMPLES:
     case LOCAL_GL_RENDERBUFFER_WIDTH:
     case LOCAL_GL_RENDERBUFFER_HEIGHT:
     case LOCAL_GL_RENDERBUFFER_RED_SIZE:
     case LOCAL_GL_RENDERBUFFER_GREEN_SIZE:
     case LOCAL_GL_RENDERBUFFER_BLUE_SIZE:
     case LOCAL_GL_RENDERBUFFER_ALPHA_SIZE:
     case LOCAL_GL_RENDERBUFFER_DEPTH_SIZE:
         {

--- a/dom/canvas/WebGLStrongTypes.h
+++ b/dom/canvas/WebGLStrongTypes.h
@@ -400,16 +400,17 @@ STRONG_GLENUM_BEGIN(FBStatus)
     STRONG_GLENUM_VALUE(FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT),
     STRONG_GLENUM_VALUE(FRAMEBUFFER_INCOMPLETE_DIMENSIONS),
     STRONG_GLENUM_VALUE(FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER),
     STRONG_GLENUM_VALUE(FRAMEBUFFER_INCOMPLETE_READ_BUFFER),
     STRONG_GLENUM_VALUE(FRAMEBUFFER_UNSUPPORTED),
 STRONG_GLENUM_END(FBStatus)
 
 STRONG_GLENUM_BEGIN(RBParam)
+    STRONG_GLENUM_VALUE(RENDERBUFFER_SAMPLES),
     STRONG_GLENUM_VALUE(RENDERBUFFER_WIDTH),
     STRONG_GLENUM_VALUE(RENDERBUFFER_HEIGHT),
     STRONG_GLENUM_VALUE(RENDERBUFFER_INTERNAL_FORMAT),
     STRONG_GLENUM_VALUE(RENDERBUFFER_RED_SIZE),
     STRONG_GLENUM_VALUE(RENDERBUFFER_GREEN_SIZE),
     STRONG_GLENUM_VALUE(RENDERBUFFER_BLUE_SIZE),
     STRONG_GLENUM_VALUE(RENDERBUFFER_ALPHA_SIZE),
     STRONG_GLENUM_VALUE(RENDERBUFFER_DEPTH_SIZE),