Media Foundation for Clear: Fix DCHECK in RendererFactorySelector

A recent change refactored how
MediaFactory::CreateRendererFactorySelector determine whether to add
the default factory or not. This missed the initial submission of the
logic for allowing Media Foundation for Clear. This resulted in a
DCHECK as the default factory would be set after the Media Foundation
factory and as a result we would always just use the Default factory.

Fix is to ensure that we set is_base_renderer_factory_set for the Media
Foundation for Clear case.

Bug: 1277243
Change-Id: Ib573ffe1f9bb665dd2055bda119ec9e8240976e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3321347
Reviewed-by: Frank Li <frankli@microsoft.com>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Commit-Queue: William Carr <wicarr@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#949226}

content/renderer/media/media_factory.cc

@@ -693,6 +693,7 @@ MediaFactory::CreateRendererFactorySelector(
       // already a base factory type set. Instead manually set the new base
       // factory type with SetBaseRendererType.
       factory_selector->SetBaseRendererType(RendererType::kMediaFoundation);
+      is_base_renderer_factory_set = true;
     }
   }
 #endif  // BUILDFLAG(IS_WIN)