content_renderer: Depend on libyuv even if WebRTC is not enabled.

video_decoder_shim.cc uses libyuv, and the build fails if we're not
building in component=shared_library mode and enable_webrtc=0:

In file included from ../../third_party/libyuv/include/libyuv.h:15:0,
                 from ../../content/renderer/pepper/video_decoder_shim.cc:25:
../../third_party/libyuv/include/libyuv/compare.h:14:32: fatal error: libyuv/basic_types.h: No such file or directory
 #include "libyuv/basic_types.h"
                                ^

R=dmichael@chromium.org, bbudge@chromium.org

Review URL: https://codereview.chromium.org/393813002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283541 0039d316-1c4b-4281-b951-d872f2087c98

content/content_renderer.gypi

@@ -849,6 +849,7 @@
         '../ppapi/ppapi_internal.gyp:ppapi_host',
         '../ppapi/ppapi_internal.gyp:ppapi_proxy',
         '../ppapi/ppapi_internal.gyp:ppapi_shared',
+        '../third_party/libyuv/libyuv.gyp:libyuv',
       ],
     }, {  # enable_plugins==0
       'sources!': [