Fix D3D11 polygon offset.

We were not taking the state of GL_POLYGON_OFFSET_FILL into account.

BUG=371604

Change-Id: I9b490ed043faeece86665acaef0b865bf1f7b60d
Reviewed-on: https://chromium-review.googlesource.com/199121
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Nicolas Capens <nicolascapens@chromium.org>

src/libGLESv2/renderer/d3d11/RenderStateCache.cpp

@@ -248,14 +248,23 @@ ID3D11RasterizerState *RenderStateCache::getRasterizerState(const gl::Rasterizer
         rasterDesc.FillMode = D3D11_FILL_SOLID;
         rasterDesc.CullMode = cullMode;
         rasterDesc.FrontCounterClockwise = (rasterState.frontFace == GL_CCW) ? FALSE: TRUE;
-        rasterDesc.DepthBias = ldexp(rasterState.polygonOffsetUnits, -static_cast<int>(depthSize));
         rasterDesc.DepthBiasClamp = 0.0f; // MSDN documentation of DepthBiasClamp implies a value of zero will preform no clamping, must be tested though.
-        rasterDesc.SlopeScaledDepthBias = rasterState.polygonOffsetFactor;
         rasterDesc.DepthClipEnable = TRUE;
         rasterDesc.ScissorEnable = scissorEnabled ? TRUE : FALSE;
         rasterDesc.MultisampleEnable = rasterState.multiSample;
         rasterDesc.AntialiasedLineEnable = FALSE;
 
+        if (rasterState.polygonOffsetFill)
+        {
+            rasterDesc.SlopeScaledDepthBias = rasterState.polygonOffsetFactor;
+            rasterDesc.DepthBias = ldexp(rasterState.polygonOffsetUnits, -static_cast<int>(depthSize));
+        }
+        else
+        {
+            rasterDesc.SlopeScaledDepthBias = 0.0f;
+            rasterDesc.DepthBias = 0.0f;
+        }
+
         ID3D11RasterizerState *dx11RasterizerState = NULL;
         HRESULT result = mDevice->CreateRasterizerState(&rasterDesc, &dx11RasterizerState);
         if (FAILED(result) || !dx11RasterizerState)