Add RTC_ prefix to (D)CHECKs and related macros.

webrtc/base/platform_thread.cc

Index: webrtc/base/platform_thread.cc
diff --git a/webrtc/base/platform_thread.cc b/webrtc/base/platform_thread.cc
index 973f7f7cf1c30468de0ee7adad8b57d0c2fa5c8f..4167392363039e8a4225c8431ddd8ba9ba3f3c08 100644
--- a/webrtc/base/platform_thread.cc
+++ b/webrtc/base/platform_thread.cc
@@ -37,7 +37,7 @@ PlatformThreadId CurrentThreadId() {
   ret = reinterpret_cast<pid_t>(pthread_self());
 #endif
 #endif  // defined(WEBRTC_POSIX)
-  DCHECK(ret);
+  RTC_DCHECK(ret);
   return ret;
 }
 
@@ -58,7 +58,7 @@ bool IsThreadRefEqual(const PlatformThreadRef& a, const PlatformThreadRef& b) {
 }
 
 void SetCurrentThreadName(const char* name) {
-  DCHECK(strlen(name) < 64);
+  RTC_DCHECK(strlen(name) < 64);
 #if defined(WEBRTC_WIN)
   struct {
     DWORD dwType;