Remove duplicated source listing of gtest_prod_util.h

This should have been done in
https://webrtc-codereview.appspot.com/39579004

BUG=
R=andresp@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/46779004

Cr-Commit-Position: refs/heads/master@{#8908}
diff --git a/webrtc/test/BUILD.gn b/webrtc/test/BUILD.gn
index fa251d6..cfb089f 100644
--- a/webrtc/test/BUILD.gn
+++ b/webrtc/test/BUILD.gn
@@ -43,7 +43,6 @@
     "testsupport/frame_reader.h",
     "testsupport/frame_writer.cc",
     "testsupport/frame_writer.h",
-    "testsupport/gtest_prod_util.h",
     "testsupport/gtest_disable.h",
     "testsupport/mock/mock_frame_reader.h",
     "testsupport/mock/mock_frame_writer.h",
@@ -58,6 +57,7 @@
   deps = [
     "//testing/gmock",
     "//testing/gtest",
+    "..:gtest_prod",
     "../system_wrappers",
   ]
 
diff --git a/webrtc/test/test.gyp b/webrtc/test/test.gyp
index ce0045b..e464aac 100644
--- a/webrtc/test/test.gyp
+++ b/webrtc/test/test.gyp
@@ -101,6 +101,7 @@
       'dependencies': [
         '<(DEPTH)/testing/gtest.gyp:gtest',
         '<(DEPTH)/testing/gmock.gyp:gmock',
+        '<(webrtc_root)/common.gyp:gtest_prod',
         '<(webrtc_root)/system_wrappers/system_wrappers.gyp:system_wrappers',
       ],
       'sources': [
@@ -110,7 +111,6 @@
         'testsupport/frame_reader.h',
         'testsupport/frame_writer.cc',
         'testsupport/frame_writer.h',
-        'testsupport/gtest_prod_util.h',
         'testsupport/gtest_disable.h',
         'testsupport/mock/mock_frame_reader.h',
         'testsupport/mock/mock_frame_writer.h',