Added Uint8ClampedList. COmpielr optimziations to follow in next CL.

runtime/vm/object_store.h

Index: runtime/vm/object_store.h
===================================================================
--- runtime/vm/object_store.h	(revision 15794)
+++ runtime/vm/object_store.h	(working copy)
@@ -178,6 +178,13 @@
     uint8_array_class_ = value.raw();
   }
 
+  RawClass* uint8_clamped_array_class() const {
+    return uint8_clamped_array_class_;
+  }
+  void set_uint8_clamped_array_class(const Class& value) {
+    uint8_clamped_array_class_ = value.raw();
+  }
+
   RawClass* int16_array_class() const {
     return int16_array_class_;
   }
@@ -248,6 +255,13 @@
     external_uint8_array_class_ = value.raw();
   }
 
+  RawClass* external_uint8_clamped_array_class() const {
+    return external_uint8_clamped_array_class_;
+  }
+  void set_external_uint8_clamped_array_class(const Class& value) {
+    external_uint8_clamped_array_class_ = value.raw();
+  }
+
   RawClass* external_int16_array_class() const {
     return external_int16_array_class_;
   }
@@ -494,6 +508,7 @@
   RawClass* growable_object_array_class_;
   RawClass* int8_array_class_;
   RawClass* uint8_array_class_;
+  RawClass* uint8_clamped_array_class_;
   RawClass* int16_array_class_;
   RawClass* uint16_array_class_;
   RawClass* int32_array_class_;
@@ -504,6 +519,7 @@
   RawClass* float64_array_class_;
   RawClass* external_int8_array_class_;
   RawClass* external_uint8_array_class_;
+  RawClass* external_uint8_clamped_array_class_;
   RawClass* external_int16_array_class_;
   RawClass* external_uint16_array_class_;
   RawClass* external_int32_array_class_;