Add optimized loads from ExternalUint8ClampedArrays.

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
@@ skipping 885 matching lines @@
     case kInt32ArrayCid:
       return Int32Array::kBytesPerElement;
     case kUint32ArrayCid:
       return Uint32Array::kBytesPerElement;
     case kOneByteStringCid:
       return OneByteString::kBytesPerElement;
     case kTwoByteStringCid:
       return TwoByteString::kBytesPerElement;
     case kExternalUint8ArrayCid:
       return ExternalUint8Array::kBytesPerElement;
+    case kExternalUint8ClampedArrayCid:
+      return ExternalUint8ClampedArray::kBytesPerElement;
     default:
       UNIMPLEMENTED();
       return 0;
   }
 }
 
 
 intptr_t FlowGraphCompiler::DataOffsetFor(intptr_t cid) {
   switch (cid) {
     case kArrayCid:
@@ skipping 77 matching lines @@
     if (i != largest_ix) {
       // Swap.
       CidTarget temp = (*sorted)[i];
       (*sorted)[i] = (*sorted)[largest_ix];
       (*sorted)[largest_ix] = temp;
     }
   }
 }
 
 }  // namespace dart