- Use isolate where it is appropriate.

runtime/vm/assembler.h

Index: runtime/vm/assembler.h
===================================================================
--- runtime/vm/assembler.h	(revision 36643)
+++ runtime/vm/assembler.h	(working copy)
@@ -30,12 +30,8 @@
 // to be called from code generated by the assembler.
 class ExternalLabel : public ValueObject {
  public:
-  ExternalLabel(const char* name, uword address)
-      : name_(name), address_(address) {
-    ASSERT(name != NULL);
-  }
+  explicit ExternalLabel(uword address) : address_(address) {}
 
-  const char* name() const { return name_; }
   bool is_resolved() const { return address_ != 0; }
   uword address() const {
     ASSERT(is_resolved());
@@ -43,7 +39,6 @@
   }
 
  private:
-  const char* name_;
   const uword address_;
 };