IDL: Add toRestricted{Float,Double}() helpers to V8Binding.h

Source/bindings/core/v8/V8Binding.cpp

Index: Source/bindings/core/v8/V8Binding.cpp
diff --git a/Source/bindings/core/v8/V8Binding.cpp b/Source/bindings/core/v8/V8Binding.cpp
index 866ef4f527700fb9958e424ac46f1d93eff70408..712c6454a3202caab6b5123db75a49d3c3f85b2b 100644
--- a/Source/bindings/core/v8/V8Binding.cpp
+++ b/Source/bindings/core/v8/V8Binding.cpp
@@ -519,6 +519,18 @@ float toFloat(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
     return static_cast<float>(toDouble(value, exceptionState));
 }
 
+float toRestrictedFloat(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
+{
+    float numberValue = toFloat(value, exceptionState);
+    if (exceptionState.hadException())
+        return 0;
+    if (!std::isfinite(numberValue)) {
+        exceptionState.throwTypeError("The provided float value is non-finite.");

[a.suchit2, 2015/02/20 15:03:12]

Why are we not throwing NotSupportedError from here based on specification
www.w3.org/TR/2dcontext/

Many of the canvas API should throw NotSupportedError in the case of
infinite/Nan. Because control never goes to our code for throwing these
exceptions based on specifications.

[Jens Widell, 2015/02/20 15:16:46]

We're throwing TypeError here because that's what WebIDL says to do, and WebIDL
is the specification this code primarily implements.

The specification you link to is probably simply wrong. (And also probably
obsolete: don't read /TR/ specifications!) The description of the API in
http://html.spec.whatwg.org/ does not say to throw NotSupportedError (except in
a non-normative section, which in turn is probably simply a bug). The
specification you link also says

  "Interfaces are defined in terms of Web IDL."

which is incompatible with requiring that a different type of exception should
be throw in error conditions also covered by Web IDL.

[a.suchit2, 2015/02/21 09:35:26]

Thanks Jens

+        return 0;
+    }
+    return numberValue;
+}
+
 double toDouble(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
 {
     if (value->IsNumber())
@@ -534,6 +546,18 @@ double toDouble(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
     return numberObject->NumberValue();
 }
 
+double toRestrictedDouble(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
+{
+    double numberValue = toDouble(value, exceptionState);
+    if (exceptionState.hadException())
+        return 0;
+    if (!std::isfinite(numberValue)) {
+        exceptionState.throwTypeError("The provided double value is non-finite.");

[a.suchit2, 2015/02/20 15:03:12]

same as above.

+        return 0;
+    }
+    return numberValue;
+}
+
 String toByteString(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
 {
     // Handle null default value.