includes: Make ast.h not need isolate.h any more.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index b297aba484242392c437f14a62b9108dbe962a16..6960168bdb7b1053a437fd5d29ff41707b1c29df 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -41,8 +41,10 @@
 #include "src/ic/call-optimization.h"
 #include "src/ic/ic.h"
 // GetRootConstructor
+#include "src/execution.h"
 #include "src/ic/ic-inl.h"
 #include "src/isolate-inl.h"
+#include "src/isolate.h"
 #include "src/runtime/runtime.h"
 
 #if V8_TARGET_ARCH_IA32
@@ -3518,7 +3520,7 @@ HOptimizedGraphBuilder::HOptimizedGraphBuilder(CompilationInfo* info)
   // constructor for the initial state relies on function_state_ == NULL
   // to know it's the initial state.
   function_state_ = &initial_function_state_;
-  InitializeAstVisitor(info->isolate());
+  InitializeAstVisitor(info->isolate()->stack_guard()->real_climit());
   if (top_info()->is_tracking_positions()) {
     SetSourcePosition(info->shared_info()->start_position());
   }