[Arm] Various cleanups to the Arm assembler backend.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index bb4618ae45d68fb35c8ebceb02de8f757b4b0373..fa370a870bf08beb62e0e422bfdcacb43099ed95 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -4761,9 +4761,8 @@ void BackEdgeTable::PatchAt(Code* unoptimized_code,
                             Address pc,
                             BackEdgeState target_state,
                             Code* replacement_code) {
-  static const int kInstrSize = Assembler::kInstrSize;
   Address pc_immediate_load_address = GetInterruptImmediateLoadAddress(pc);
-  Address branch_address = pc_immediate_load_address - kInstrSize;
+  Address branch_address = pc_immediate_load_address - Assembler::kInstrSize;
   CodePatcher patcher(branch_address, 1);
   switch (target_state) {
     case INTERRUPT:
@@ -4778,7 +4777,7 @@ void BackEdgeTable::PatchAt(Code* unoptimized_code,
 
       // Calculate branch offet to the ok-label - this is the difference between
       // the branch address and |pc| (which points at <blx ip>) plus one instr.
-      int branch_offset = pc + kInstrSize - branch_address;
+      int branch_offset = pc + Assembler::kInstrSize - branch_address;
       patcher.masm()->b(branch_offset, pl);
       break;
     }
@@ -4808,11 +4807,10 @@ BackEdgeTable::BackEdgeState BackEdgeTable::GetBackEdgeState(
     Isolate* isolate,
     Code* unoptimized_code,
     Address pc) {
-  static const int kInstrSize = Assembler::kInstrSize;
-  ASSERT(Memory::int32_at(pc - kInstrSize) == kBlxIp);
+  ASSERT(Assembler::IsBlxIp(Memory::int32_at(pc - Assembler::kInstrSize)));
 
   Address pc_immediate_load_address = GetInterruptImmediateLoadAddress(pc);
-  Address branch_address = pc_immediate_load_address - kInstrSize;
+  Address branch_address = pc_immediate_load_address - Assembler::kInstrSize;
   Address interrupt_address = Assembler::target_address_at(
       pc_immediate_load_address, unoptimized_code);