viz: Pass --enable-viz to renderer.

Surface sync is activated with --enable-viz now, but that wasn't being
passed to the renderer. This resulted in surfaces not showing up
sometimes.

Bug: 793302
Change-Id: Ief3a4f3a85b4ccd1b4d45d86cb4e6fcd1cf0c918
Reviewed-on: https://chromium-review.googlesource.com/825645Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Commit-Queue: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523896}

content/browser/renderer_host/render_process_host_impl.cc

@@ -2672,6 +2672,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     cc::switches::kRunAllCompositorStagesBeforeDraw,
     switches::kDisableSurfaceReferences,
     switches::kEnableSurfaceSynchronization,
+    switches::kEnableViz,
 
 #if BUILDFLAG(ENABLE_PLUGINS)
     switches::kEnablePepperTesting,