Fraction class prototype and test (not to be committed).

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index 3f5a507d3a67dc74476be205e77057f4a596ccf5..296f21a682f6d12222ac1c28983c7e60d74337b6 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -61,6 +61,7 @@ namespace dart {
         V(Smi)                                                                 \
         V(Mint)                                                                \
         V(Bigint)                                                              \
+      V(Fraction)                                                              \
       V(Double)                                                                \
     V(Bool)                                                                    \
     V(GrowableObjectArray)                                                     \
@@ -1805,6 +1806,20 @@ class RawBigint : public RawInteger {
 };
 
 
+class RawFraction : public RawNumber {
+  RAW_HEAP_OBJECT_IMPLEMENTATION(Fraction);
+
+  RawObject** from() {
+    return reinterpret_cast<RawObject**>(&ptr()->numerator_);
+  }
+  RawInteger* numerator_;
+  RawInteger* denominator_;
+  RawObject** to() {
+    return reinterpret_cast<RawObject**>(&ptr()->denominator_);
+  }
+};
+
+
 class RawDouble : public RawNumber {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Double);
 
@@ -2237,7 +2252,8 @@ inline bool RawObject::IsNumberClassId(intptr_t index) {
                  kSmiCid == kNumberCid + 2 &&
                  kMintCid == kNumberCid + 3 &&
                  kBigintCid == kNumberCid + 4 &&
-                 kDoubleCid == kNumberCid + 5);
+                 kFractionCid == kNumberCid + 5 &&
+                 kDoubleCid == kNumberCid + 6);
   return (index >= kNumberCid && index < kBoolCid);
 }
 
@@ -2247,8 +2263,8 @@ inline bool RawObject::IsIntegerClassId(intptr_t index) {
   COMPILE_ASSERT(kSmiCid == kIntegerCid + 1 &&
                  kMintCid == kIntegerCid + 2 &&
                  kBigintCid == kIntegerCid + 3 &&
-                 kDoubleCid == kIntegerCid + 4);
-  return (index >= kIntegerCid && index < kDoubleCid);
+                 kFractionCid == kIntegerCid + 4);
+  return (index >= kIntegerCid && index < kFractionCid);
 }
 
 
@@ -2416,7 +2432,7 @@ inline bool RawObject::IsVariableSizeClassId(intptr_t index) {
 // is defined by the VM but are used in the VM code by computing the
 // implicit field offsets of the various fields in the dart object.
 inline bool RawObject::IsImplicitFieldClassId(intptr_t index) {
-  return (IsTypedDataViewClassId(index) || index == kByteBufferCid);
+  return (IsTypedDataViewClassId(index) || (index == kByteBufferCid));
 }