Revert of Clean up V4L2 codec-related flags and defines

content/content_tests.gypi

Index: content/content_tests.gypi
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index 44d6cec175c47e116de71ffb771cc1f592adc731..e8c752846dbc1528534cfd24316d6defce5bea54 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -4,6 +4,7 @@
 
 {
   'variables': {
+    'use_v4lplugin%': 0,
     'layouttest_support_content_sources': [
       'public/test/layouttest_support.h',
       'public/test/nested_message_pump_android.cc',
@@ -1610,6 +1611,9 @@
                   '../ui/ozone/ozone.gyp:ozone',       # Used by rendering_helper.cc
                 ],
               }],
+              ['use_v4lplugin==1', {
+                'defines': ['USE_LIBV4L2'],
+              }],
             ],
             # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
             'msvs_disabled_warnings': [ 4267, ],