MHTML: Allows 'data:' URLs to be processed using normal request processing.

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

Index: third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
diff --git a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
index 9766e241d7248b3f7e9239d87c45176df3c85d47..0fcd890a93b05b98f9fdc73aff9044f4f9a0e7bf 100644
--- a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
+++ b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
@@ -443,12 +443,16 @@ Resource* ResourceFetcher::requestResource(FetchRequest& request, const Resource
         }
     }
 
-    bool isStaticData = request.resourceRequest().url().protocolIsData() || substituteData.isValid() || m_archive;
+    bool isDataUrl = request.resourceRequest().url().protocolIsData();
+    bool isStaticData = isDataUrl || substituteData.isValid() || m_archive;
     Resource* resource(nullptr);
     if (isStaticData) {
         resource = resourceForStaticData(request, factory, substituteData);
-        // Abort the request if the archive doesn't contain the resource.
-        if (!resource && m_archive)
+        // Abort the request if the archive doesn't contain the resource, except
+        // in the case of data URLs which might have resources such as fonts
+        // that need to be decoded only on demand.  These data URLs are allowed
+        // to be processed using the normal ResourceFetcher machinery.
+        if (!resource && !isDataUrl && m_archive)
             return nullptr;
     }
     if (!resource)