Replace the easy cases of VERIFY usage.

BUG=webrtc:6424

Review-Url: https://codereview.webrtc.org/2652653012
Cr-Commit-Position: refs/heads/master@{#16370}
diff --git a/webrtc/pc/peerconnection.cc b/webrtc/pc/peerconnection.cc
index cbd0d4b..14e1809 100644
--- a/webrtc/pc/peerconnection.cc
+++ b/webrtc/pc/peerconnection.cc
@@ -1014,7 +1014,7 @@
                               StatsOutputLevel level) {
   TRACE_EVENT0("webrtc", "PeerConnection::GetStats");
   RTC_DCHECK(signaling_thread()->IsCurrent());
-  if (!VERIFY(observer != NULL)) {
+  if (!observer) {
     LOG(LS_ERROR) << "GetStats - observer is NULL.";
     return false;
   }
@@ -1097,7 +1097,7 @@
 void PeerConnection::CreateOffer(CreateSessionDescriptionObserver* observer,
                                  const MediaConstraintsInterface* constraints) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateOffer");
-  if (!VERIFY(observer != nullptr)) {
+  if (!observer) {
     LOG(LS_ERROR) << "CreateOffer - observer is NULL.";
     return;
   }
@@ -1149,7 +1149,7 @@
 void PeerConnection::CreateOffer(CreateSessionDescriptionObserver* observer,
                                  const RTCOfferAnswerOptions& options) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateOffer");
-  if (!VERIFY(observer != nullptr)) {
+  if (!observer) {
     LOG(LS_ERROR) << "CreateOffer - observer is NULL.";
     return;
   }
@@ -1169,7 +1169,7 @@
     CreateSessionDescriptionObserver* observer,
     const MediaConstraintsInterface* constraints) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateAnswer");
-  if (!VERIFY(observer != nullptr)) {
+  if (!observer) {
     LOG(LS_ERROR) << "CreateAnswer - observer is NULL.";
     return;
   }
@@ -1188,7 +1188,7 @@
 void PeerConnection::CreateAnswer(CreateSessionDescriptionObserver* observer,
                                   const RTCOfferAnswerOptions& options) {
   TRACE_EVENT0("webrtc", "PeerConnection::CreateAnswer");
-  if (!VERIFY(observer != nullptr)) {
+  if (!observer) {
     LOG(LS_ERROR) << "CreateAnswer - observer is NULL.";
     return;
   }
@@ -1211,7 +1211,7 @@
   if (IsClosed()) {
     return;
   }
-  if (!VERIFY(observer != nullptr)) {
+  if (!observer) {
     LOG(LS_ERROR) << "SetLocalDescription - observer is NULL.";
     return;
   }
@@ -1293,7 +1293,7 @@
   if (IsClosed()) {
     return;
   }
-  if (!VERIFY(observer != nullptr)) {
+  if (!observer) {
     LOG(LS_ERROR) << "SetRemoteDescription - observer is NULL.";
     return;
   }
@@ -2190,7 +2190,8 @@
     // track label is the same as |streamid|.
     const std::string& channel_label = params.sync_label;
     auto data_channel_it = rtp_data_channels_.find(channel_label);
-    if (!VERIFY(data_channel_it != rtp_data_channels_.end())) {
+    if (data_channel_it == rtp_data_channels_.end()) {
+      LOG(LS_ERROR) << "channel label not found";
       continue;
     }
     // Set the SSRC the data channel should use for sending.