Make base::Value::TYPE a scoped enum.

components/dom_distiller/ios/distiller_page_ios.mm

Index: components/dom_distiller/ios/distiller_page_ios.mm
diff --git a/components/dom_distiller/ios/distiller_page_ios.mm b/components/dom_distiller/ios/distiller_page_ios.mm
index a59548ae016bd82f1a14ebf921b252233d3ddbd1..8ae4962c07eb3141a760777cf400f6621656aafd 100644
--- a/components/dom_distiller/ios/distiller_page_ios.mm
+++ b/components/dom_distiller/ios/distiller_page_ios.mm
@@ -46,24 +46,24 @@ std::unique_ptr<base::Value> ValueResultFromScriptResult(id wk_result,
   CFTypeID result_type = CFGetTypeID(wk_result);
   if (result_type == CFStringGetTypeID()) {
     result.reset(new base::StringValue(base::SysNSStringToUTF16(wk_result)));
-    DCHECK(result->IsType(base::Value::TYPE_STRING));
+    DCHECK(result->IsType(base::Value::Type::STRING));
   } else if (result_type == CFNumberGetTypeID()) {
     // Different implementation is here.
     if ([wk_result intValue] != [wk_result doubleValue]) {
       result.reset(new base::FundamentalValue([wk_result doubleValue]));
-      DCHECK(result->IsType(base::Value::TYPE_DOUBLE));
+      DCHECK(result->IsType(base::Value::Type::DOUBLE));
     } else {
       result.reset(new base::FundamentalValue([wk_result intValue]));
-      DCHECK(result->IsType(base::Value::TYPE_INTEGER));
+      DCHECK(result->IsType(base::Value::Type::INTEGER));
     }
     // End of different implementation.
   } else if (result_type == CFBooleanGetTypeID()) {
     result.reset(
         new base::FundamentalValue(static_cast<bool>([wk_result boolValue])));
-    DCHECK(result->IsType(base::Value::TYPE_BOOLEAN));
+    DCHECK(result->IsType(base::Value::Type::BOOLEAN));
   } else if (result_type == CFNullGetTypeID()) {
     result = base::Value::CreateNullValue();
-    DCHECK(result->IsType(base::Value::TYPE_NULL));
+    DCHECK(result->IsType(base::Value::Type::NONE));
   } else if (result_type == CFDictionaryGetTypeID()) {
     std::unique_ptr<base::DictionaryValue> dictionary =
         base::MakeUnique<base::DictionaryValue>();