media: Use DefaultCdmFactory when ENABLE_MOJO_CDM is false

When ENABLE_MOJO_CDM is false, we should still support ClearKey key
system, hence use DefaultCdmFactory in this case.

Thanks to yucliu@ for finding this issue.

Change-Id: I72d730497daefb6c0c2709915a9ee3ec482e1125
Reviewed-on: https://chromium-review.googlesource.com/c/1324191Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606198}

content/renderer/media/media_factory.cc

@@ -66,6 +66,8 @@
 
 #if BUILDFLAG(ENABLE_MOJO_CDM)
 #include "media/mojo/clients/mojo_cdm_factory.h"  // nogncheck
+#else
+#include "media/cdm/default_cdm_factory.h"
 #endif
 
 #if BUILDFLAG(ENABLE_MOJO_RENDERER)
@@ -622,6 +624,8 @@ media::CdmFactory* MediaFactory::GetCdmFactory() {
 
 #if BUILDFLAG(ENABLE_MOJO_CDM)
   cdm_factory_.reset(new media::MojoCdmFactory(GetMediaInterfaceFactory()));
+#else
+  cdm_factory_.reset(new media::DefaultCdmFactory());
 #endif  // BUILDFLAG(ENABLE_MOJO_CDM)
 
   return cdm_factory_.get();