Remove the dependency of Zone on Isolate

src/compiler.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_H_
 #define V8_COMPILER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
@@ skipping 511 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(CompilationInfo);
 };
 
 
 // Exactly like a CompilationInfo, except also creates and enters a
 // Zone on construction and deallocates it on exit.
 class CompilationInfoWithZone: public CompilationInfo {
  public:
   explicit CompilationInfoWithZone(Handle<Script> script)
-      : CompilationInfo(script, &zone_),
-        zone_(script->GetIsolate()) {}
+      : CompilationInfo(script, &zone_) {}
   explicit CompilationInfoWithZone(Handle<SharedFunctionInfo> shared_info)
-      : CompilationInfo(shared_info, &zone_),
-        zone_(shared_info->GetIsolate()) {}
+      : CompilationInfo(shared_info, &zone_) {}
   explicit CompilationInfoWithZone(Handle<JSFunction> closure)
-      : CompilationInfo(closure, &zone_),
-        zone_(closure->GetIsolate()) {}
+      : CompilationInfo(closure, &zone_) {}
   CompilationInfoWithZone(HydrogenCodeStub* stub, Isolate* isolate)
-      : CompilationInfo(stub, isolate, &zone_),
-        zone_(isolate) {}
+      : CompilationInfo(stub, isolate, &zone_) {}
   CompilationInfoWithZone(ScriptCompiler::ExternalSourceStream* stream,
                           ScriptCompiler::StreamedSource::Encoding encoding,
                           Isolate* isolate)
-      : CompilationInfo(stream, encoding, isolate, &zone_), zone_(isolate) {}
+      : CompilationInfo(stream, encoding, isolate, &zone_) {}
 
   // Virtual destructor because a CompilationInfoWithZone has to exit the
   // zone scope and get rid of dependent maps even when the destructor is
   // called when cast as a CompilationInfo.
   virtual ~CompilationInfoWithZone() {
     RollbackDependencies();
   }
 
  private:
   Zone zone_;
@@ skipping 196 matching lines @@
   Zone zone_;
   unsigned info_zone_start_allocation_size_;
   base::ElapsedTimer timer_;
 
   DISALLOW_COPY_AND_ASSIGN(CompilationPhase);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_COMPILER_H_