Use auto-rethrowing v8::TryCatch variant

Source/bindings/v8/V8BindingMacros.h

Index: Source/bindings/v8/V8BindingMacros.h
diff --git a/Source/bindings/v8/V8BindingMacros.h b/Source/bindings/v8/V8BindingMacros.h
index ac4fa714f71defb4f72aff8f4672cd33a1e93dc9..1dc394acfe3ba66c63af186c05df988d07bff798 100644
--- a/Source/bindings/v8/V8BindingMacros.h
+++ b/Source/bindings/v8/V8BindingMacros.h
@@ -47,17 +47,16 @@ namespace WebCore {
     }
 
 #define TONATIVE_VOID_INTERNAL(var, value) \
-    var = (value);                        \
-    if (UNLIKELY(block.HasCaught())) {    \
-        block.ReThrow();                  \
-        return;                           \
-    }
+    var = (value);                         \
+    if (UNLIKELY(block.HasCaught()))       \
+        return;
 
-#define TONATIVE_VOID(type, var, value)    \
-    type var;                              \
-    {                                      \
-        v8::TryCatch block;                \
-        TONATIVE_VOID_INTERNAL(var, value); \
+#define TONATIVE_VOID(type, var, value)        \
+    type var;                                  \
+    {                                          \
+        v8::TryCatch block;                    \
+        V8RethrowTryCatchScope rethrow(block); \

[haraken, 2014/05/30 11:58:25]

In my understanding, V8RethrowTryCatchScope should always be coupled with
v8::TryCatch. Would it be possible to merge the two classes, so that we can just
write this as:

V8TryCatchRethrowScope scope;

?

[yhirano, 2014/05/30 12:06:58]

I would like to "overwrite" V8RethrowTryCatchScope's effect by placing another
V8ResetTryCatchScope inside its scope (and that's why V8ResetTryCatchScope
exists), in another CL.

+        TONATIVE_VOID_INTERNAL(var, value);    \
     }
 
 #define TONATIVE_DEFAULT(type, var, value, retVal) \
@@ -106,15 +105,7 @@ namespace WebCore {
 
 #define TOSTRING_VOID_INTERNAL(var, value) \
     var = (value);                         \
-    if (UNLIKELY(!var.prepare())) {        \
-        block.ReThrow();                   \
-        return;                            \
-    }
-
-// There are no v8::TryCatch declared outside.
-#define TOSTRING_VOID_INTERNAL_NOTRYCATCH(var, value) \
-    var = (value);                                    \
-    if (UNLIKELY(!var.prepare()))                     \
+    if (UNLIKELY(!var.prepare()))          \
         return;
 
 #define TOSTRING_DEFAULT(type, var, value, retVal) \