Fix FixedDoubleArray crashes in chromebot

src/runtime.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 201 matching lines @@
             { MaybeObject* maybe_result = DeepCopyBoilerplate(isolate,
                                                               js_object);
               if (!maybe_result->ToObject(&result)) return maybe_result;
             }
             element_dictionary->ValueAtPut(i, result);
           }
         }
       }
       break;
     }
-    default:
-      UNREACHABLE();
+    case JSObject::NON_STRICT_ARGUMENTS_ELEMENTS:
+      UNIMPLEMENTED();
+      break;
+    case JSObject::EXTERNAL_PIXEL_ELEMENTS:
+    case JSObject::EXTERNAL_BYTE_ELEMENTS:
+    case JSObject::EXTERNAL_UNSIGNED_BYTE_ELEMENTS:
+    case JSObject::EXTERNAL_SHORT_ELEMENTS:
+    case JSObject::EXTERNAL_UNSIGNED_SHORT_ELEMENTS:
+    case JSObject::EXTERNAL_INT_ELEMENTS:
+    case JSObject::EXTERNAL_UNSIGNED_INT_ELEMENTS:
+    case JSObject::EXTERNAL_FLOAT_ELEMENTS:
+    case JSObject::EXTERNAL_DOUBLE_ELEMENTS:
+    case JSObject::FAST_DOUBLE_ELEMENTS:
+      // No contained objects, nothing to do.
       break;
   }
   return copy;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_CloneLiteralBoilerplate) {
   CONVERT_CHECKED(JSObject, boilerplate, args[0]);
   return DeepCopyBoilerplate(isolate, boilerplate);
 }
@@ skipping 12517 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal