--- a/dom/canvas/WebGLContext.h
+++ b/dom/canvas/WebGLContext.h
@@ -969,16 +969,17 @@ public:
 
 private:
     // State tracking slots
     realGLboolean mDitherEnabled;
     realGLboolean mRasterizerDiscardEnabled;
     realGLboolean mScissorTestEnabled;
     realGLboolean mDepthTestEnabled;
     realGLboolean mStencilTestEnabled;
+    GLenum mGenerateMipmapHint;
 
     bool ValidateCapabilityEnum(GLenum cap, const char* info);
     realGLboolean* GetStateTrackingSlot(GLenum cap);
 
 // -----------------------------------------------------------------------------
 // Texture funcions (WebGLContextTextures.cpp)
 public:
     void ActiveTexture(GLenum texUnit);

--- a/dom/canvas/WebGLContextGL.cpp
+++ b/dom/canvas/WebGLContextGL.cpp
@@ -942,16 +942,18 @@ WebGLContext::Hint(GLenum target, GLenum
 {
     if (IsContextLost())
         return;
 
     bool isValid = false;
 
     switch (target) {
     case LOCAL_GL_GENERATE_MIPMAP_HINT:
+        mGenerateMipmapHint = mode;
+
         // Deprecated and removed in desktop GL Core profiles.
         if (gl->IsCoreProfile())
             return;
 
         isValid = true;
         break;
 
     case LOCAL_GL_FRAGMENT_SHADER_DERIVATIVE_HINT:

--- a/dom/canvas/WebGLContextState.cpp
+++ b/dom/canvas/WebGLContextState.cpp
@@ -381,22 +381,25 @@ WebGLContext::GetParameter(JSContext* cx
         case LOCAL_GL_STENCIL_BACK_PASS_DEPTH_FAIL:
         case LOCAL_GL_STENCIL_BACK_PASS_DEPTH_PASS:
         case LOCAL_GL_DEPTH_FUNC:
         case LOCAL_GL_BLEND_SRC_RGB:
         case LOCAL_GL_BLEND_SRC_ALPHA:
         case LOCAL_GL_BLEND_DST_RGB:
         case LOCAL_GL_BLEND_DST_ALPHA:
         case LOCAL_GL_BLEND_EQUATION_RGB:
-        case LOCAL_GL_BLEND_EQUATION_ALPHA:
-        case LOCAL_GL_GENERATE_MIPMAP_HINT: {
+        case LOCAL_GL_BLEND_EQUATION_ALPHA: {
             GLint i = 0;
             gl->fGetIntegerv(pname, &i);
             return JS::NumberValue(uint32_t(i));
         }
+
+        case LOCAL_GL_GENERATE_MIPMAP_HINT:
+            return JS::NumberValue(mGenerateMipmapHint);
+
         case LOCAL_GL_IMPLEMENTATION_COLOR_READ_TYPE: {
             const webgl::FormatUsageInfo* usage;
             uint32_t width, height;
             if (!ValidateCurFBForRead(funcName, &usage, &width, &height))
                 return JS::NullValue();
 
             GLint i = 0;
             if (gl->IsSupported(gl::GLFeature::ES2_compatibility)) {

--- a/dom/canvas/WebGLContextValidate.cpp
+++ b/dom/canvas/WebGLContextValidate.cpp
@@ -496,16 +496,17 @@ WebGLContext::InitAndValidateGL(FailureR
     AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_VALUE_MASK,      mStencilValueMaskFront);
     AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_BACK_VALUE_MASK, mStencilValueMaskBack);
     AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_WRITEMASK,       mStencilWriteMaskFront);
     AssertUintParamCorrect(gl, LOCAL_GL_STENCIL_BACK_WRITEMASK,  mStencilWriteMaskBack);
 
     mDitherEnabled = true;
     mRasterizerDiscardEnabled = false;
     mScissorTestEnabled = false;
+    mGenerateMipmapHint = LOCAL_GL_DONT_CARE;
 
     // Bindings, etc.
     mActiveTexture = 0;
     mDefaultFB_DrawBuffer0 = LOCAL_GL_BACK;
 
     mEmitContextLostErrorOnce = true;
     mWebGLError = LOCAL_GL_NO_ERROR;
     mUnderlyingGLError = LOCAL_GL_NO_ERROR;