Remove WIN32 support from sandbox_export.h

sandbox/sandbox_export.h

Index: sandbox/sandbox_export.h
diff --git a/sandbox/sandbox_export.h b/sandbox/sandbox_export.h
index 0b773034ba4a3f46fa3749d1fcf79ae3b5b00169..40a403664062c7846da62b208238e3dce30a6b6b 100644
--- a/sandbox/sandbox_export.h
+++ b/sandbox/sandbox_export.h
@@ -5,16 +5,11 @@
 #ifndef SANDBOX_SANDBOX_EXPORT_H_
 #define SANDBOX_SANDBOX_EXPORT_H_
 
-#if defined(COMPONENT_BUILD)
 #if defined(WIN32)
+#error "sandbox_export.h does not support WIN32."
+#endif
 
-#if defined(SANDBOX_IMPLEMENTATION)
-#define SANDBOX_EXPORT __declspec(dllexport)
-#else
-#define SANDBOX_EXPORT __declspec(dllimport)
-#endif  // defined(GFX_IMPLEMENTATION)
-
-#else  // defined(WIN32)
+#if defined(COMPONENT_BUILD)
 
 #if defined(SANDBOX_IMPLEMENTATION)
 #define SANDBOX_EXPORT __attribute__((visibility("default")))
@@ -24,7 +19,6 @@
 #define SANDBOX_EXPORT_PRIVATE
 #endif  // defined(SANDBOX_IMPLEMENTATION)
 
-#endif  // defined(WIN32)
 #else  // defined(COMPONENT_BUILD)
 
 #define SANDBOX_EXPORT