--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -1017,18 +1017,20 @@ CanvasRenderingContext2D::Redraw(const m
   nsSVGEffects::InvalidateDirectRenderingObservers(mCanvasElement);
 
   mCanvasElement->InvalidateCanvasContent(&r);
 }
 
 void
 CanvasRenderingContext2D::DidRefresh()
 {
-  SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
-  if (glue) {
+  if (IsTargetValid() && SkiaGLTex()) {
+    SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
+    MOZ_ASSERT(glue);
+
     auto gl = glue->GetGLContext();
     gl->FlushIfHeavyGLCallsSinceLastFlush();
   }
 }
 
 void
 CanvasRenderingContext2D::RedrawUser(const gfxRect& r)
 {
@@ -4818,16 +4820,24 @@ CanvasRenderingContext2D::CreateImageDat
                                           ErrorResult& error)
 {
   return mozilla::dom::CreateImageData(cx, this, imagedata.Width(),
                                        imagedata.Height(), error);
 }
 
 static uint8_t g2DContextLayerUserData;
 
+
+uint32_t
+CanvasRenderingContext2D::SkiaGLTex() const
+{
+    MOZ_ASSERT(IsTargetValid());
+    return (uint32_t)(uintptr_t)mTarget->GetNativeSurface(NativeSurfaceType::OPENGL_TEXTURE);
+}
+
 already_AddRefed<CanvasLayer>
 CanvasRenderingContext2D::GetCanvasLayer(nsDisplayListBuilder* aBuilder,
                                          CanvasLayer *aOldLayer,
                                          LayerManager *aManager)
 {
   if (mOpaque) {
     // If we're opaque then make sure we have a surface so we paint black
     // instead of transparent.
@@ -4849,19 +4859,21 @@ CanvasRenderingContext2D::GetCanvasLayer
 
   if (!mResetLayer && aOldLayer) {
     CanvasRenderingContext2DUserData* userData =
       static_cast<CanvasRenderingContext2DUserData*>(
         aOldLayer->GetUserData(&g2DContextLayerUserData));
 
     CanvasLayer::Data data;
 
-    SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
-    GLuint skiaGLTex = (GLuint)(uintptr_t)mTarget->GetNativeSurface(NativeSurfaceType::OPENGL_TEXTURE);
-    if (glue && skiaGLTex) {
+    GLuint skiaGLTex = SkiaGLTex();
+    if (skiaGLTex) {
+      SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
+      MOZ_ASSERT(glue);
+
       data.mGLContext = glue->GetGLContext();
       data.mFrontbufferGLTex = skiaGLTex;
     } else {
       data.mDrawTarget = mTarget;
     }
 
     if (userData && userData->IsForContext(this) && aOldLayer->IsDataValid(data)) {
       nsRefPtr<CanvasLayer> ret = aOldLayer;
@@ -4893,21 +4905,24 @@ CanvasRenderingContext2D::GetCanvasLayer
   canvasLayer->SetDidTransactionCallback(
           CanvasRenderingContext2DUserData::DidTransactionCallback, userData);
   canvasLayer->SetUserData(&g2DContextLayerUserData, userData);
 
   CanvasLayer::Data data;
   data.mSize = nsIntSize(mWidth, mHeight);
   data.mHasAlpha = !mOpaque;
 
-  SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
-  GLuint skiaGLTex = (GLuint)(uintptr_t)mTarget->GetNativeSurface(NativeSurfaceType::OPENGL_TEXTURE);
-  if (glue && skiaGLTex) {
+  GLuint skiaGLTex = SkiaGLTex();
+  if (skiaGLTex) {
     canvasLayer->SetPreTransactionCallback(
             CanvasRenderingContext2DUserData::PreTransactionCallback, userData);
+
+    SkiaGLGlue* glue = gfxPlatform::GetPlatform()->GetSkiaGLGlue();
+    MOZ_ASSERT(glue);
+
     data.mGLContext = glue->GetGLContext();
     data.mFrontbufferGLTex = skiaGLTex;
   } else {
     data.mDrawTarget = mTarget;
   }
 
   canvasLayer->Initialize(data);
   uint32_t flags = mOpaque ? Layer::CONTENT_OPAQUE : 0;

--- a/dom/canvas/CanvasRenderingContext2D.h
+++ b/dom/canvas/CanvasRenderingContext2D.h
@@ -693,17 +693,19 @@ protected:
   /*
    * Disposes an old target and prepares to lazily create a new target.
    */
   void ClearTarget();
 
   /**
    * Check if the target is valid after calling EnsureTarget.
    */
-  bool IsTargetValid() { return mTarget != sErrorTarget && mTarget != nullptr; }
+  bool IsTargetValid() const {
+    return mTarget != sErrorTarget && mTarget != nullptr;
+  }
 
   /**
     * Returns the surface format this canvas should be allocated using. Takes
     * into account mOpaque, platform requirements, etc.
     */
   mozilla::gfx::SurfaceFormat GetSurfaceFormat() const;
 
   /**
@@ -759,16 +761,18 @@ protected:
   // If mCanvasElement is not provided, then a docshell is
   nsCOMPtr<nsIDocShell> mDocShell;
 
   // This is created lazily so it is necessary to call EnsureTarget before
   // accessing it. In the event of an error it will be equal to
   // sErrorTarget.
   mozilla::RefPtr<mozilla::gfx::DrawTarget> mTarget;
 
+  uint32_t SkiaGLTex() const;
+
   /**
     * Flag to avoid duplicate calls to InvalidateFrame. Set to true whenever
     * Redraw is called, reset to false when Render is called.
     */
   bool mIsEntireFrameInvalid;
   /**
     * When this is set, the first call to Redraw(gfxRect) should set
     * mIsEntireFrameInvalid since we expect it will be followed by