Make GetDefaultThreadStackSize() return 16M under ThreadSanitizer

base/threading/platform_thread_linux.cc

Index: base/threading/platform_thread_linux.cc
===================================================================
--- base/threading/platform_thread_linux.cc	(revision 245989)
+++ base/threading/platform_thread_linux.cc	(working copy)
@@ -100,7 +100,13 @@
 void TerminateOnThread() {}
 
 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
+#if !defined(THREAD_SANITIZER)
   return 0;
+#else
+  // ThreadSanitizer bloats the stack heavily. Evidence has been that the
+  // default stack size isn't enough for some browser tests.
+  return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).
+#endif
 }
 
 }  // namespace base