Support conversion of clamped double values for pixel arrays in Crankshaft.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index ddba47f9a5c39d630adaf60b7fef073556839d6c..84c487bfd9e85a70604e4a93048c91a8d1cff990 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -3722,6 +3722,11 @@ HInstruction* HGraphBuilder::BuildStoreKeyedSpecializedArrayElement(
   HLoadExternalArrayPointer* external_elements =
       new(zone()) HLoadExternalArrayPointer(elements);
   AddInstruction(external_elements);
+  if (expr->external_array_type() == kExternalPixelArray) {
+    HClampToUint8* clamp = new(zone()) HClampToUint8(val);
+    AddInstruction(clamp);
+    val = clamp;
+  }
   return new(zone()) HStoreKeyedSpecializedArrayElement(
       external_elements,
       key,