API functions returning Promises should not throw exceptions.

Source/bindings/core/v8/V8BindingMacros.h

Index: Source/bindings/core/v8/V8BindingMacros.h
diff --git a/Source/bindings/core/v8/V8BindingMacros.h b/Source/bindings/core/v8/V8BindingMacros.h
index 165d5b7b0144f1c7756a018f4110c2bc2a598063..798d5b36ec0d8884dd95b740be61987d154a6e17 100644
--- a/Source/bindings/core/v8/V8BindingMacros.h
+++ b/Source/bindings/core/v8/V8BindingMacros.h
@@ -70,6 +70,24 @@ namespace blink {
         }                                          \
     }
 
+// We need to cancel the exception propergation when we return a rejected
+// Promise.
+#define TONATIVE_VOID_PROMISE_INTERNAL(var, value, info)                                        \
+    var = (value);                                                                              \
+    if (UNLIKELY(block.HasCaught())) {                                                          \
+        v8SetReturnValue(info, ScriptPromise::rejectRaw(info.GetIsolate(), block.Exception())); \
+        block.Reset();                                                                          \
+        return;                                                                                 \
+    }
+
+#define TONATIVE_VOID_PROMISE(type, var, value, info)     \
+    type var;                                             \
+    {                                                     \
+        v8::TryCatch block;                               \
+        TONATIVE_VOID_PROMISE_INTERNAL(var, value, info); \
+    }
+
+
 #define TONATIVE_VOID_EXCEPTIONSTATE_INTERNAL(var, value, exceptionState) \
     var = (value);                                                        \
     if (UNLIKELY(block.HasCaught() || exceptionState.throwIfNeeded()))    \
@@ -93,6 +111,27 @@ namespace blink {
             return retVal;                                                        \
     }
 
+// We need to cancel the exception propergation when we return a rejected
+// Promise.
+#define TONATIVE_VOID_EXCEPTIONSTATE_PROMISE_INTERNAL(var, value, exceptionState, info, scriptState) \
+    var = (value);                                                                                   \
+    if (UNLIKELY(block.HasCaught())) {                                                               \
+        v8SetReturnValue(info, ScriptPromise::rejectRaw(info.GetIsolate(), block.Exception()));      \
+        block.Reset();                                                                               \
+        return;                                                                                      \
+    }                                                                                                \
+    if (UNLIKELY(exceptionState.hadException())) {                                                   \
+        v8SetReturnValue(info, exceptionState.reject(scriptState).v8Value());                        \
+        return;                                                                                      \
+    }
+
+#define TONATIVE_VOID_EXCEPTIONSTATE_PROMISE(type, var, value, exceptionState, info, scriptState)     \
+    type var;                                                                                         \
+    {                                                                                                 \
+        v8::TryCatch block;                                                                           \
+        TONATIVE_VOID_EXCEPTIONSTATE_PROMISE_INTERNAL(var, value, exceptionState, info, scriptState); \
+    }
+
 // type is an instance of class template V8StringResource<>,
 // but Mode argument varies; using type (not Mode) for consistency
 // with other macros and ease of code generation
@@ -111,6 +150,23 @@ namespace blink {
     if (UNLIKELY(!var.prepare()))                  \
         return retVal;
 
+// We need to cancel the exception propergation when we return a rejected
+// Promise.
+#define TOSTRING_VOID_PROMISE_INTERNAL(var, value, info)                                           \
+    var = (value);                                                                                 \
+    if (UNLIKELY(!var.prepare()))  {                                                               \
+        info.GetReturnValue().Set(ScriptPromise::rejectRaw(info.GetIsolate(), block.Exception())); \
+        block.Reset();                                                                             \
+        return;                                                                                    \
+    }
+
+#define TOSTRING_VOID_PROMISE(type, var, value, info)           \
+    type var;                                                   \
+    {                                                           \
+        v8::TryCatch block;                                     \
+        TOSTRING_VOID_PROMISE_INTERNAL(type, var, value, info); \
+    }
+
 } // namespace blink
 
 #endif // V8BindingMacros_h