Allow chrome-proxy-content-transform:identity as legal response header

components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc

Index: components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc
diff --git a/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc b/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc
index fe139ab1121e5d3cc1ebfcf990d717e82a748317..eb75b49b502021f54176df6687fad0b55ab0530d 100644
--- a/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc
+++ b/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc
@@ -43,6 +43,7 @@ const char kActionValueDelimiter = '=';
 const char kEmptyImageDirective[] = "empty-image";
 const char kLitePageDirective[] = "lite-page";
 const char kCompressedVideoDirective[] = "compressed-video";
+const char kIdentityDirective[] = "identity";
 const char kChromeProxyPagePoliciesDirective[] = "page-policies";
 
 // The legacy Chrome-Proxy response header directive for LoFi images.
@@ -233,6 +234,10 @@ TransformDirective ParseResponseTransform(
   } else if (base::LowerCaseEqualsASCII(content_transform_value,
                                         empty_image_directive())) {
     return TRANSFORM_EMPTY_IMAGE;
+  } else if (base::LowerCaseEqualsASCII(content_transform_value,
+                                        kIdentityDirective)) {
+    // Open Original Image - not really a transform.
+    return TRANSFORM_NONE;
   } else {
     NOTREACHED() << "Unexpected content transform header: "
                  << content_transform_value;