Remove grab-bag includes of v8.h from several files.

src/allocation-tracker.h

Index: src/allocation-tracker.h
diff --git a/src/allocation-tracker.h b/src/allocation-tracker.h
index f3788b91a66ab5cff4a71fec5fb5e6b1035d571e..c409f2437bb4341e33b5c9daa7db753de7f5bc96 100644
--- a/src/allocation-tracker.h
+++ b/src/allocation-tracker.h
@@ -7,12 +7,21 @@
 
 #include <map>
 
+#include "include/v8-profiler.h"
+#include "src/handles.h"
+#include "src/hashmap.h"
+#include "src/list.h"
+#include "src/vector.h"
+
 namespace v8 {
 namespace internal {
 
-class HeapObjectsMap;
-
+// Forward declarations.
 class AllocationTraceTree;
+class AllocationTracker;
+class HeapObjectsMap;
+class SharedFunctionInfo;
+class StringsStorage;
 
 class AllocationTraceNode {
  public: