Disentangle assembler from isolate.

src/arm/assembler-arm-inl.h

Index: src/arm/assembler-arm-inl.h
diff --git a/src/arm/assembler-arm-inl.h b/src/arm/assembler-arm-inl.h
index 661895d82592973a7575da4f8722b00ae0abd250..50b5ea2053861b13bd5eb07801907e07db2fbf34 100644
--- a/src/arm/assembler-arm-inl.h
+++ b/src/arm/assembler-arm-inl.h
@@ -114,7 +114,7 @@ void RelocInfo::set_target_object(HeapObject* target,
                                   WriteBarrierMode write_barrier_mode,
                                   ICacheFlushMode icache_flush_mode) {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
-  Assembler::set_target_address_at(isolate_, pc_, host_,
+  Assembler::set_target_address_at(target->GetIsolate(), pc_, host_,
                                    reinterpret_cast<Address>(target),
                                    icache_flush_mode);
   if (write_barrier_mode == UPDATE_WRITE_BARRIER && host() != NULL) {
@@ -148,13 +148,12 @@ Address RelocInfo::target_runtime_entry(Assembler* origin) {
   return target_address();
 }
 
-
-void RelocInfo::set_target_runtime_entry(Address target,
+void RelocInfo::set_target_runtime_entry(Isolate* isolate, Address target,
                                          WriteBarrierMode write_barrier_mode,
                                          ICacheFlushMode icache_flush_mode) {
   DCHECK(IsRuntimeEntry(rmode_));
   if (target_address() != target)
-    set_target_address(target, write_barrier_mode, icache_flush_mode);
+    set_target_address(isolate, target, write_barrier_mode, icache_flush_mode);
 }
 
 
@@ -213,8 +212,7 @@ Address RelocInfo::debug_call_address() {
   return Memory::Address_at(pc_ + Assembler::kPatchDebugBreakSlotAddressOffset);
 }
 
-
-void RelocInfo::set_debug_call_address(Address target) {
+void RelocInfo::set_debug_call_address(Isolate* isolate, Address target) {
   DCHECK(IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence());
   Memory::Address_at(pc_ + Assembler::kPatchDebugBreakSlotAddressOffset) =
       target;
@@ -225,15 +223,14 @@ void RelocInfo::set_debug_call_address(Address target) {
   }
 }
 
-
-void RelocInfo::WipeOut() {
+void RelocInfo::WipeOut(Isolate* isolate) {
   DCHECK(IsEmbeddedObject(rmode_) || IsCodeTarget(rmode_) ||
          IsRuntimeEntry(rmode_) || IsExternalReference(rmode_) ||
          IsInternalReference(rmode_));
   if (IsInternalReference(rmode_)) {
     Memory::Address_at(pc_) = NULL;
   } else {
-    Assembler::set_target_address_at(isolate_, pc_, host_, NULL);
+    Assembler::set_target_address_at(isolate, pc_, host_, NULL);
   }
 }
 
@@ -527,6 +524,7 @@ Address Assembler::target_address_at(Address pc, Address constant_pool) {
 void Assembler::set_target_address_at(Isolate* isolate, Address pc,
                                       Address constant_pool, Address target,
                                       ICacheFlushMode icache_flush_mode) {
+  DCHECK_IMPLIES(isolate == nullptr, icache_flush_mode == SKIP_ICACHE_FLUSH);
   if (is_constant_pool_load(pc)) {
     // This is a constant pool lookup. Update the entry in the constant pool.
     Memory::Address_at(constant_pool_entry_address(pc, constant_pool)) = target;