Reland "Soft fail for invalid cache data."

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 820e1494e5711d0914d6acdefbe96168821c82ea..b362951af9bcc32d5e93123b12ebb3f530634c58 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -62,10 +62,14 @@ class FunctionEntry BASE_EMBEDDED {
 // Wrapper around ScriptData to provide parser-specific functionality.
 class ParseData {
  public:
-  explicit ParseData(ScriptData* script_data) : script_data_(script_data) {
-    CHECK(IsAligned(script_data->length(), sizeof(unsigned)));
-    CHECK(IsSane());
+  static ParseData* FromCachedData(ScriptData* cached_data) {
+    ParseData* pd = new ParseData(cached_data);
+    if (pd->IsSane()) return pd;
+    cached_data->Reject();
+    delete pd;
+    return NULL;
   }
+
   void Initialize();
   FunctionEntry GetFunctionEntry(int start);
   int FunctionCount();
@@ -77,6 +81,8 @@ class ParseData {
   }
 
  private:
+  explicit ParseData(ScriptData* script_data) : script_data_(script_data) {}
+
   bool IsSane();
   unsigned Magic();
   unsigned Version();
@@ -722,6 +728,13 @@ class Parser : public ParserBase<ParserTraits> {
   ScriptCompiler::CompileOptions compile_options() const {
     return info_->compile_options();
   }
+  bool consume_cached_parse_data() const {
+    return compile_options() == ScriptCompiler::kConsumeParserCache &&
+           cached_parse_data_ != NULL;
+  }
+  bool produce_cached_parse_data() const {
+    return compile_options() == ScriptCompiler::kProduceParserCache;
+  }
   Scope* DeclarationScope(VariableMode mode) {
     return IsLexicalVariableMode(mode)
         ? scope_ : scope_->DeclarationScope();