Merge mozilla-central to b2g-inbound

      ToClientLayer(GetMaskLayer())->RenderLayer();

    }

    // For more complex cases we need to calculate a bunch of metrics before we

    // can do the paint.

    BeginPaint();

    if (mPaintData.mPaintFinished) {

      return;

    }

    // In some cases we can take a fast path and just be done with it.

    if (UseFastPath()) {

      TILING_LOG("TILING %p: Taking fast-path\n", this);

      mValidRegion = neededRegion;

      mContentClient->mTiledBuffer.PaintThebes(mValidRegion, invalidRegion, callback, data);

      ClientManager()->Hold(this);

      mContentClient->UseTiledLayerBuffer(TiledContentClient::TILED_BUFFER);

      // Make sure that tiles that fall outside of the visible region or outside of the

      // critical displayport are discarded on the first update. Also make sure that we

      // only draw stuff inside the critical displayport on the first update.

      if (!mPaintData.mCriticalDisplayPort.IsEmpty()) {

        mValidRegion.And(mValidRegion, LayerIntRect::ToUntyped(mPaintData.mCriticalDisplayPort));

        invalidRegion.And(invalidRegion, LayerIntRect::ToUntyped(mPaintData.mCriticalDisplayPort));

      }

      if (invalidRegion.IsEmpty()) {

        EndPaint();

        return;

      }

    // For more complex cases we need to calculate a bunch of metrics before we

    // can do the paint.

    BeginPaint();

    if (mPaintData.mPaintFinished) {

      mContentClient->mTiledBuffer.SetFrameResolution(mPaintData.mResolution);

      mContentClient->mTiledBuffer.PaintThebes(mValidRegion, invalidRegion, callback, data);

      ClientManager()->Hold(this);

      mContentClient->UseTiledLayerBuffer(TiledContentClient::TILED_BUFFER);

      EndPaint();

      return;

    }