Cleanup timeline stream enabled flag so that it can be easily tested from an intrinsic

runtime/vm/thread.h

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_THREAD_H_
 #define VM_THREAD_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 30 matching lines @@
 class RawBool;
 class RawObject;
 class RawCode;
 class RawError;
 class RawGrowableObjectArray;
 class RawString;
 class RuntimeEntry;
 class Smi;
 class StackResource;
 class String;
+class TimelineStream;
 class TypeArguments;
 class TypeParameter;
 class Zone;
 
 #define REUSABLE_HANDLE_LIST(V)                                                \
   V(AbstractType)                                                              \
   V(Array)                                                                     \
   V(Class)                                                                     \
   V(Code)                                                                      \
   V(Error)                                                                     \
@@ skipping 202 matching lines @@
   void set_api_top_scope(ApiLocalScope* value) { api_top_scope_ = value; }
 
   // The isolate that this thread is operating on, or NULL if none.
   Isolate* isolate() const { return isolate_; }
   static intptr_t isolate_offset() {
     return OFFSET_OF(Thread, isolate_);
   }
   bool IsMutatorThread() const;
   bool CanCollectGarbage() const;
 
+  // Offset of Dart TimelineStream object.
+  static intptr_t dart_stream_offset() {
+    return OFFSET_OF(Thread, dart_stream_);
+  }
+
   // Is |this| executing Dart code?
   bool IsExecutingDartCode() const;
 
   // Has |this| exited Dart code?
   bool HasExitedDartCode() const;
 
   // The (topmost) CHA for the compilation in this thread.
   CHA* cha() const {
     ASSERT(isolate_ != NULL);
     return cha_;
@@ skipping 342 matching lines @@
 
   void InitVMConstants();
 
  private:
   template<class T> T* AllocateReusableHandle();
 
   // Accessed from generated code:
   uword stack_limit_;
   uword stack_overflow_flags_;
   Isolate* isolate_;
+  TimelineStream* dart_stream_;
   Heap* heap_;
   uword top_exit_frame_info_;
   StoreBufferBlock* store_buffer_block_;
   uword vm_tag_;
   TaskKind task_kind_;
   // State that is cached in the TLS for fast access in generated code.
 #define DECLARE_MEMBERS(type_name, member_name, expr, default_init_value)      \
   type_name member_name;
 CACHED_CONSTANTS_LIST(DECLARE_MEMBERS)
 #undef DECLARE_MEMBERS
@@ skipping 112 matching lines @@
 // Disable thread interrupts.
 class DisableThreadInterruptsScope : public StackResource {
  public:
   explicit DisableThreadInterruptsScope(Thread* thread);
   ~DisableThreadInterruptsScope();
 };
 
 }  // namespace dart
 
 #endif  // VM_THREAD_H_