Assert that context creation doesn't throw

src/execution.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_EXECUTION_H_
 #define V8_EXECUTION_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/handles.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
 
 class Execution final : public AllStatic {
  public:
+  // Whether to report pending messages, or keep them pending on the isolate.
+  enum class MessageHandling { kReport, kKeepPending };
+
   // Call a function, the caller supplies a receiver and an array
   // of arguments.
   //
   // When the function called is not in strict mode, receiver is
   // converted to an object.
   //
   V8_EXPORT_PRIVATE MUST_USE_RESULT static MaybeHandle<Object> Call(
       Isolate* isolate, Handle<Object> callable, Handle<Object> receiver,
       int argc, Handle<Object> argv[]);
 
   // Construct object from function, the caller supplies an array of
   // arguments.
   MUST_USE_RESULT static MaybeHandle<Object> New(Handle<JSFunction> constructor,
                                                  int argc,
                                                  Handle<Object> argv[]);
   MUST_USE_RESULT static MaybeHandle<Object> New(Isolate* isolate,
                                                  Handle<Object> constructor,
                                                  Handle<Object> new_target,
                                                  int argc,
                                                  Handle<Object> argv[]);
 
-  // Call a function, just like Call(), but make sure to silently catch
-  // any thrown exceptions. The return value is either the result of
-  // calling the function (if caught exception is false) or the exception
-  // that occurred (if caught exception is true).
-  // In the exception case, exception_out holds the caught exceptions, unless
-  // it is a termination exception.
+  // Call a function, just like Call(), but handle don't report exceptions
+  // externally.
+  // The return value is either the result of calling the function (if no
+  // exception occurred), or an empty handle.
+  // If message_handling is MessageHandling::kReport, exceptions (except for
+  // termination exceptions) will be stored in exception_out (if not a
+  // nullptr).
   static MaybeHandle<Object> TryCall(Isolate* isolate, Handle<Object> callable,
                                      Handle<Object> receiver, int argc,
                                      Handle<Object> argv[],
-                                     MaybeHandle<Object>* exception_out = NULL);
+                                     MessageHandling message_handling,
+                                     MaybeHandle<Object>* exception_out);
 };
 
 
 class ExecutionAccess;
 class PostponeInterruptsScope;
 
 
 // StackGuard contains the handling of the limits that are used to limit the
 // number of nested invocations of JavaScript and the stack size used in each
 // invocation.
@@ skipping 159 matching lines @@
   friend class StackLimitCheck;
   friend class PostponeInterruptsScope;
 
   DISALLOW_COPY_AND_ASSIGN(StackGuard);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_EXECUTION_H_