Add a DCHECK for PlatformThread instances that are too busy.

webrtc/base/platform_thread_unittest.cc

Index: webrtc/base/platform_thread_unittest.cc
diff --git a/webrtc/base/platform_thread_unittest.cc b/webrtc/base/platform_thread_unittest.cc
index d6d35e40e4955dfe82367ac29e3ed2de00c1efbf..b11e336df20bae25869c2b4c3a16c1656457f8df 100644
--- a/webrtc/base/platform_thread_unittest.cc
+++ b/webrtc/base/platform_thread_unittest.cc
@@ -21,6 +21,11 @@ bool NullRunFunctionDeprecated(void* obj) {
   return true;
 }
 
+bool TooBusyRunFunction(void* obj) {
+  // Indentionally busy looping.
+  return true;
+}
+
 void NullRunFunction(void* obj) {}
 
 // Function that sets a boolean.
@@ -108,4 +113,11 @@ TEST(PlatformThreadTest, RunFunctionIsCalled) {
   EXPECT_TRUE(flag);
 }
 
+TEST(PlatformThreadTest, DISABLED_TooBusyDeprecated) {
+  PlatformThread thread(&TooBusyRunFunction, nullptr, "BusyThread");
+  thread.Start();
+  webrtc::SleepMs(1000);
+  thread.Stop();
+}
+
 }  // rtc