[WIP] Add DCHECK for mojo::edk::Init().

mojo/edk/embedder/embedder.cc

Index: mojo/edk/embedder/embedder.cc
diff --git a/mojo/edk/embedder/embedder.cc b/mojo/edk/embedder/embedder.cc
index 5cf70e5f416231880109c0ea5aedaabb324b7711..f4ef70617ace50993e9a7580528e6148a2320d5d 100644
--- a/mojo/edk/embedder/embedder.cc
+++ b/mojo/edk/embedder/embedder.cc
@@ -22,21 +22,16 @@
 #include "mojo/edk/system/core.h"
 
 #if !defined(OS_NACL)
+#include "base/debug/stack_trace.h"
 #include "crypto/random.h"
 #endif
 
 namespace mojo {
 namespace edk {
-
-class Core;
-class PlatformSupport;
-
 namespace internal {
 
-Core* g_core;
-ProcessDelegate* g_process_delegate;
-
-Core* GetCore() { return g_core; }
+Core* g_core = nullptr;
+ProcessDelegate* g_process_delegate = nullptr;
 
 }  // namespace internal
 
@@ -98,7 +93,13 @@ void Init() {
   MojoSystemThunks thunks = MakeSystemThunks();
   size_t expected_size = MojoEmbedderSetSystemThunks(&thunks);
   DCHECK_EQ(expected_size, sizeof(thunks));
-
+#if defined(OS_NACL) || 1
+  DCHECK(!internal::g_core) << "No nacl stack trace.";
+#else
+  static std::string prev_stack;
+  DCHECK(!internal::g_core) << prev_stack << "\nEndOfPrevStack";
+  prev_stack = base::debug::StackTrace().ToString();
+#endif
   internal::g_core = new Core();
 }
 
@@ -140,6 +141,13 @@ MojoResult PassSharedMemoryHandle(
 void InitIPCSupport(ProcessDelegate* process_delegate,
                     scoped_refptr<base::TaskRunner> io_thread_task_runner) {
   CHECK(internal::g_core);
+#if defined(OS_NACL) || 1
+  DCHECK(!internal::g_process_delegate) << "No stack trace on NaCl";
+#else
+  static std::string prev_stack;
+  DCHECK(!internal::g_process_delegate) << prev_stack << "\nEndOfPrevStack";
+  prev_stack = base::debug::StackTrace().ToString();
+#endif
   internal::g_core->SetIOTaskRunner(io_thread_task_runner);
   internal::g_process_delegate = process_delegate;
 }
@@ -150,6 +158,7 @@ void ShutdownIPCSupport() {
   internal::g_core->RequestShutdown(
       base::Bind(&ProcessDelegate::OnShutdownComplete,
                  base::Unretained(internal::g_process_delegate)));
+  internal::g_process_delegate = nullptr;
 }
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
@@ -161,18 +170,18 @@ void SetMachPortProvider(base::PortProvider* port_provider) {
 
 ScopedMessagePipeHandle CreateMessagePipe(
     ScopedPlatformHandle platform_handle) {
-  CHECK(internal::g_process_delegate);
+  CHECK(internal::g_core);
   return internal::g_core->CreateMessagePipe(std::move(platform_handle));
 }
 
 ScopedMessagePipeHandle CreateParentMessagePipe(
     const std::string& token, const std::string& child_token) {
-  CHECK(internal::g_process_delegate);
+  CHECK(internal::g_core);
   return internal::g_core->CreateParentMessagePipe(token, child_token);
 }
 
 ScopedMessagePipeHandle CreateChildMessagePipe(const std::string& token) {
-  CHECK(internal::g_process_delegate);
+  CHECK(internal::g_core);
   return internal::g_core->CreateChildMessagePipe(token);
 }