Replace NULL with nullptr in all C++ files.

webrtc/base/autodetectproxy_unittest.cc

Index: webrtc/base/autodetectproxy_unittest.cc
diff --git a/webrtc/base/autodetectproxy_unittest.cc b/webrtc/base/autodetectproxy_unittest.cc
index 2ae7a6aa255428408385ceeffdb980c9ed9e67ed..90b9d34683d1ad6288136ce07a99557e4f29ddff 100644
--- a/webrtc/base/autodetectproxy_unittest.cc
+++ b/webrtc/base/autodetectproxy_unittest.cc
@@ -33,7 +33,7 @@ static const int kTimeoutMs = 10000;
 
 class AutoDetectProxyTest : public testing::Test, public sigslot::has_slots<> {
  public:
-  AutoDetectProxyTest() : auto_detect_proxy_(NULL), done_(false) {}
+  AutoDetectProxyTest() : auto_detect_proxy_(nullptr), done_(false) {}
 
  protected:
   bool Create(const std::string& user_agent,
@@ -43,7 +43,7 @@ class AutoDetectProxyTest : public testing::Test, public sigslot::has_slots<> {
               bool secure,
               bool startnow) {
     auto_detect_proxy_ = new AutoDetectProxy(user_agent);
-    EXPECT_TRUE(auto_detect_proxy_ != NULL);
+    EXPECT_TRUE(auto_detect_proxy_ != nullptr);
     if (!auto_detect_proxy_) {
       return false;
     }
@@ -90,7 +90,7 @@ class AutoDetectProxyTest : public testing::Test, public sigslot::has_slots<> {
     AutoDetectProxy *auto_detect_proxy =
         static_cast<rtc::AutoDetectProxy *>(thread);
     EXPECT_TRUE(auto_detect_proxy == auto_detect_proxy_);
-    auto_detect_proxy_ = NULL;
+    auto_detect_proxy_ = nullptr;
     auto_detect_proxy->Release();
     done_ = true;
   }