Update V8 to r7427: Initial merge by git

As required by WebKit r82507

Change-Id: I7ae83ef3f689356043b4929255b7c1dd31d8c5df
diff --git a/src/arm/assembler-arm-inl.h b/src/arm/assembler-arm-inl.h
index 3b81102..bd76d9a 100644
--- a/src/arm/assembler-arm-inl.h
+++ b/src/arm/assembler-arm-inl.h
@@ -203,11 +203,12 @@
   } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
     visitor->VisitExternalReference(target_reference_address());
 #ifdef ENABLE_DEBUGGER_SUPPORT
-  } else if (Debug::has_break_points() &&
-             ((RelocInfo::IsJSReturn(mode) &&
+  // TODO(isolates): Get a cached isolate below.
+  } else if (((RelocInfo::IsJSReturn(mode) &&
               IsPatchedReturnSequence()) ||
              (RelocInfo::IsDebugBreakSlot(mode) &&
-              IsPatchedDebugBreakSlotSequence()))) {
+              IsPatchedDebugBreakSlotSequence())) &&
+             Isolate::Current()->debug()->has_break_points()) {
     visitor->VisitDebugTarget(this);
 #endif
   } else if (mode == RelocInfo::RUNTIME_ENTRY) {
@@ -217,10 +218,10 @@
 
 
 template<typename StaticVisitor>
-void RelocInfo::Visit() {
+void RelocInfo::Visit(Heap* heap) {
   RelocInfo::Mode mode = rmode();
   if (mode == RelocInfo::EMBEDDED_OBJECT) {
-    StaticVisitor::VisitPointer(target_object_address());
+    StaticVisitor::VisitPointer(heap, target_object_address());
   } else if (RelocInfo::IsCodeTarget(mode)) {
     StaticVisitor::VisitCodeTarget(this);
   } else if (mode == RelocInfo::GLOBAL_PROPERTY_CELL) {
@@ -228,7 +229,7 @@
   } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
     StaticVisitor::VisitExternalReference(target_reference_address());
 #ifdef ENABLE_DEBUGGER_SUPPORT
-  } else if (Debug::has_break_points() &&
+  } else if (heap->isolate()->debug()->has_break_points() &&
              ((RelocInfo::IsJSReturn(mode) &&
               IsPatchedReturnSequence()) ||
              (RelocInfo::IsDebugBreakSlot(mode) &&