Clean up forward declarations in Source/modules

Source/modules/webdatabase/InspectorDatabaseAgent.h

Index: Source/modules/webdatabase/InspectorDatabaseAgent.h
diff --git a/Source/modules/webdatabase/InspectorDatabaseAgent.h b/Source/modules/webdatabase/InspectorDatabaseAgent.h
index 3bbb18de85332d1eb1ccde36087eaf48b770fbf3..9843f88f6e73de27cf5eda8a49df2866c32e5255 100644
--- a/Source/modules/webdatabase/InspectorDatabaseAgent.h
+++ b/Source/modules/webdatabase/InspectorDatabaseAgent.h
@@ -31,19 +31,12 @@
 
 #include "core/InspectorFrontend.h"
 #include "core/inspector/InspectorBaseAgent.h"
-#include "platform/heap/Handle.h"
-#include "wtf/HashMap.h"
-#include "wtf/PassOwnPtr.h"
-#include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class Database;
-class DocumentLoader;
-class LocalFrame;
 class InspectorDatabaseResource;
 class InspectorFrontend;
-class InstrumentingAgents;
 
 typedef String ErrorString;