Ensure MimeHandlerView plugins load properly with long URLs

extensions/browser/api/mime_handler_private/mime_handler_private.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/api/mime_handler_private/mime_handler_private.h"
 
 #include "base/strings/string_util.h"
 #include "content/public/browser/stream_handle.h"
 #include "content/public/browser/stream_info.h"
+#include "content/public/common/content_constants.h"
 #include "extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h"
 #include "extensions/common/constants.h"
 #include "net/http/http_response_headers.h"
 #include "third_party/mojo/src/mojo/public/cpp/bindings/map.h"
 
 namespace extensions {
 namespace {
 
 mojo::Map<mojo::String, mojo::String> CreateResponseHeadersMap(
     const net::HttpResponseHeaders* headers) {
@@ skipping 72 matching lines @@
     extensions::StreamContainer>::Convert(const extensions::StreamContainer&
                                               stream) {
   if (!stream.stream_info()->handle)
     return extensions::mime_handler::StreamInfoPtr();
 
   auto result = extensions::mime_handler::StreamInfo::New();
   result->embedded = stream.embedded();
   result->tab_id = stream.tab_id();
   const content::StreamInfo* info = stream.stream_info();
   result->mime_type = info->mime_type;
-  result->original_url = info->original_url.spec();
+
+  // If the URL is too long, mojo will give up on sending the URL. In these
+  // cases truncate it. Only data: URLs should ever really suffer this problem
+  // so only worry about those for now.
+  // TODO(raymes): This appears to be a bug in mojo somewhere. crbug.com/480099.
+  if (info->original_url.SchemeIs(url::kDataScheme) &&
+      info->original_url.spec().size() > content::kMaxURLDisplayChars) {
+    result->original_url = info->original_url.scheme() + ":";
+  } else {
+    result->original_url = info->original_url.spec();
+  }
+
   result->stream_url = info->handle->GetURL().spec();
   result->response_headers =
       extensions::CreateResponseHeadersMap(info->response_headers.get());
   return result.Pass();
 }
 
 }  // namespace mojo