Implements a new API to set a function entry hook for profiling.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 48cd780c6a43ec3a4ebb57f0fc4a54663d8896ac..43148e73ed9372985ec384b402635b7c41992634 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -142,6 +142,12 @@ bool LCodeGen::GeneratePrologue() {
   }
 #endif
 
+  const FunctionEntryHook* hook_location = V8::GetFunctionEntryHookLocation();
+  if (*hook_location != NULL) {
+    ProfileEntryHookStub stub;
+    __ CallStub(&stub);
+  }
+
   // Strict mode functions and builtins need to replace the receiver
   // with undefined when called as functions (without an explicit
   // receiver object). ecx is zero for method calls and non-zero for