vp8_impl.cc: Rename postproc field trial string for arm.

BUG=webrtc:6634

Review-Url: https://codereview.webrtc.org/3006143002
Cr-Original-Commit-Position: refs/heads/master@{#19713}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: a505fb021f62898d282b8eae072dd73ee1eccc6a
diff --git a/modules/video_coding/codecs/vp8/vp8_impl.cc b/modules/video_coding/codecs/vp8/vp8_impl.cc
index 3bf85d5..c84049f 100644
--- a/modules/video_coding/codecs/vp8/vp8_impl.cc
+++ b/modules/video_coding/codecs/vp8/vp8_impl.cc
@@ -40,7 +40,7 @@
 namespace webrtc {
 namespace {
 
-const char kVp8PostProcArmFieldTrial[] = "WebRTC-VP8-Postproc-Arm";
+const char kVp8PostProcArmFieldTrial[] = "WebRTC-VP8-Postproc-Config-Arm";
 const char kVp8GfBoostFieldTrial[] = "WebRTC-VP8-GfBoost";
 const char kVp8ForceFallbackEncoderFieldTrial[] =
     "WebRTC-VP8-Forced-Fallback-Encoder";