This reverts commit 63ba357c.

Reason for revert: May be causing Windows GPU.FYI bot failures.

https://ci.chromium.org/buildbot/chromium.gpu.fyi/Win10%20Release%20%28Intel%20HD%20630%29/1443

maps_pixel_test on Intel GPU:
Unexpected Failures:
* gpu_tests.maps_integration_test.MapsIntegrationTest.Maps_maps

webgl2_conformance_tests on Intel GPU:
Unexpected Failures:
* gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_deqp_functional_gles3_fboinvalidate_default
* gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_deqp_functional_gles3_fboinvalidate_sub

Bug: chromium:798757

Original change's description:
> Enable depth buffer to workaround driver bug on Intel windows
>
> Rendering with depth buffer disabled and stencil buffer enabled
> leads to memory leak if we set viewport a large size on Intel
> windows platforms. So we enable depth buffer if stencil buffer
> is enabled to workaround this issue.
>
> TEST=gl_test.exe --gtest_filter=GLClearFramebufferTestWithParam/GLClearFramebufferTest.ClearDepthStencil/0
> TEST=conformance/rendering/rendering-stencil-large-viewport.html
> TEST=RenderStencilBufferTest.DrawWithLargeViewport/ES3_D3D11
>
> BUG=782317
>
> Change-Id: Idb185db296f13e3fa897534514e198651a56439f
> Reviewed-on: https://chromium-review.googlesource.com/809574
> Commit-Queue: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>

TBR=zmo@chromium.org,geofflang@chromium.org,jmadill@chromium.org,kbr@chromium.org,cwallez@chromium.org,yunchao.he@intel.com,jiajia.qin@intel.com,xinghua.cao@intel.com,bryan.bernhart@intel.com,yizhou.jiang@intel.com,yang.gu@intel.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 782317
Change-Id: I7e29da683b22fd4640c230598c7b220cfae6a177
Reviewed-on: https://chromium-review.googlesource.com/848133
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>