Minor cleanups: use GrowableArray::is_empty instead of ::length() == 0

runtime/vm/flow_graph_compiler.h

 // Copyright (c) 2012, 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_FLOW_GRAPH_COMPILER_H_
 #define VM_FLOW_GRAPH_COMPILER_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/assembler_macros.h"
@@ skipping 39 matching lines @@
 
   // Perform a greedy local register allocation.  Consider all register free.
   void AllocateRegisters(Instruction* instr);
 
   // Spill all live registers to the stack in order from oldest to newest.
   void Spill();
 
   // Returns true if all live values are stored on the stack.
   // Code generator expects no live values in registers at call sites and
   // branches.
-  bool IsSpilled() const { return stack_.length() == 0; }
+  bool IsSpilled() const { return stack_.is_empty(); }
 
   // Popuplate deoptimization stub with live registers to ensure
   // that they will be pushed to the stack when deoptimization happens.
   void SpillInDeoptStub(DeoptimizationStub* stub);
 
  private:
   // Pop a value from the place where it is currently stored (either register
   // or top of the stack) into a given register.  If value is in the register
   // verify that passed use corresponds to the instruction that produced the
   // value.
@@ skipping 101 matching lines @@
 #include "vm/flow_graph_compiler_ia32.h"
 #elif defined(TARGET_ARCH_X64)
 #include "vm/flow_graph_compiler_x64.h"
 #elif defined(TARGET_ARCH_ARM)
 #include "vm/flow_graph_compiler_arm.h"
 #else
 #error Unknown architecture.
 #endif
 
 #endif  // VM_FLOW_GRAPH_COMPILER_H_