Make V8ValueConverter.FromV8Value behave similarly to JSON.stringify

content/public/renderer/v8_value_converter.h

Index: content/public/renderer/v8_value_converter.h
diff --git a/content/public/renderer/v8_value_converter.h b/content/public/renderer/v8_value_converter.h
index be45ea9d3f56325e181ce057cbe10026f2f2e7ca..0d8236548522848c8376ecdc7d0e9f8f9a347751 100644
--- a/content/public/renderer/v8_value_converter.h
+++ b/content/public/renderer/v8_value_converter.h
@@ -30,8 +30,19 @@ class CONTENT_EXPORT V8ValueConverter {
 
   // Use the following setters to support additional types other than the
   // default ones.
-  virtual bool GetUndefinedAllowed() const = 0;
-  virtual void SetUndefinedAllowed(bool val) = 0;
+
+  enum UndefinedValueBehavior {
+    // Treat undefined values as errors. This is the default behavior.
+    TREAT_AS_ERROR,

[not at google - send to devlin, 2012/09/11 11:50:11]

The existence of "treat as error" only makes if trying to maintain the behaviour
where we logged warnings when trying to convert undefined. I don't know how
useful that is.

Ideally all this configuration stuff would be deleted and OMIT would be implied.

(at least, make it the default and delete TREAT_AS_ERROR).

WDYT?

[koz (OOO until 15th September), 2012/09/12 02:08:28]

As discussed, seeing as this logs errors to STDERR in debug builds it's probably
not doing extension developers any good so it's fine to remove it.

+
+    // Treat undefined values as inconvertible and omit them from the result.
+    OMIT,
+
+    // Convert undefined values to null.
+    CONVERT_TO_NULL
+  };
+  virtual UndefinedValueBehavior GetUndefinedValueBehavior() const = 0;
+  virtual void SetUndefinedValueBehavior(UndefinedValueBehavior val) = 0;
 
   virtual bool GetDateAllowed() const = 0;
   virtual void SetDateAllowed(bool val) = 0;
@@ -43,16 +54,24 @@ class CONTENT_EXPORT V8ValueConverter {
   virtual bool GetStripNullFromObjects() const = 0;
   virtual void SetStripNullFromObjects(bool val) = 0;
 
-  // Converts Value to v8::Value. Unsupported types are replaced with null.
-  // If an array or object throws while setting a value, that property or item
-  // is skipped, leaving a hole in the case of arrays.
+  // Converts a base::Value to a v8::Value.
+  //
+  // Unsupported types are replaced with null.  If an array or object throws
+  // while setting a value, that property or item is skipped, leaving a hole in
+  // the case of arrays.
   virtual v8::Handle<v8::Value> ToV8Value(
       const base::Value* value,
       v8::Handle<v8::Context> context) const = 0;
 
-  // Converts v8::Value to Value. Unsupported types are replaced with null.
-  // If an array or object throws while getting a value, that property or item
-  // is replaced with null.
+  // Converts a v8::Value to base::Value.
+  //
+  // Unsupported types (unless explicitly configured) are not converted, so
+  // this method may return NULL -- the exception is when converting arrays,
+  // where unsupported types are converted to Value(TYPE_NULL).

[koz (OOO until 15th September), 2012/09/12 02:08:28]

where unsupported types -> where elements that have unsupported types

+  //
+  // Likewise, if an object throws while converting a property it will not be
+  // converted, whereas if an array throws while converting an item it will be

[koz (OOO until 15th September), 2012/09/12 02:08:28]

Perhaps better phrased as:

If an object throws while converting a property, the resulting base::Value will
omit that property altogether. If an exception is thrown while converting an
element of an array the resulting array will have a Value(TYPE_NULL) in the
corresponding position.

+  // converted to Value(TYPE_NULL).
   virtual base::Value* FromV8Value(v8::Handle<v8::Value> value,
                                    v8::Handle<v8::Context> context) const = 0;
 };