Fix non-functional nit in videoadapter

We should DCHECK alignment of width, not height.

BUG=None

Review-Url: https://codereview.webrtc.org/2726543002
Cr-Original-Commit-Position: refs/heads/master@{#16904}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 4e836828f436082179e8d9a4fbf57b7a1a0a9a18
diff --git a/media/base/videoadapter.cc b/media/base/videoadapter.cc
index 589be63..522d175 100644
--- a/media/base/videoadapter.cc
+++ b/media/base/videoadapter.cc
@@ -218,7 +218,7 @@
   // Calculate final output size.
   *out_width = *cropped_width / scale.denominator * scale.numerator;
   *out_height = *cropped_height / scale.denominator * scale.numerator;
-  RTC_DCHECK_EQ(0, *out_height % required_resolution_alignment_);
+  RTC_DCHECK_EQ(0, *out_width % required_resolution_alignment_);
   RTC_DCHECK_EQ(0, *out_height % required_resolution_alignment_);
 
   ++frames_out_;