Componentization: make symbols visible.

Source/modules/fetch/CompositeDataConsumerHandle.h

Index: Source/modules/fetch/CompositeDataConsumerHandle.h
diff --git a/Source/modules/fetch/CompositeDataConsumerHandle.h b/Source/modules/fetch/CompositeDataConsumerHandle.h
index a39d6d384b7965dbabebb85616affc6fd9aa582d..48c926439e8b8d81eabdc8de510a3b3ca84bd3d9 100644
--- a/Source/modules/fetch/CompositeDataConsumerHandle.h
+++ b/Source/modules/fetch/CompositeDataConsumerHandle.h
@@ -5,6 +5,7 @@
 #ifndef CompositeDataConsumerHandle_h
 #define CompositeDataConsumerHandle_h
 
+#include "modules/ModulesExport.h"
 #include "public/platform/WebDataConsumerHandle.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
@@ -15,7 +16,7 @@ namespace blink {
 // This is a utility class to construct a composite data consumer handle. It
 // owns a web data consumer handle and delegates methods. A user can update
 // the handle by using |update| method.
-class CompositeDataConsumerHandle final : public WebDataConsumerHandle {
+class MODULES_EXPORT CompositeDataConsumerHandle final : public WebDataConsumerHandle {
 public:
     // |handle| must not be null and must not be locked.
     static PassOwnPtr<CompositeDataConsumerHandle> create(PassOwnPtr<WebDataConsumerHandle> handle)