Fix: Loading cid: resources in WebView.

third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp

Index: third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp
diff --git a/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp b/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp
index 57ae8dea3348a3cfbe41ae484093189103aced6d..2622ea588061ab9126ebf9ca2e47252448f757be 100644
--- a/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp
+++ b/third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp
@@ -644,10 +644,15 @@ Resource* ResourceFetcher::RequestResource(
                                     params.Options().initiator_info.name);
   }
 
-  // An URL with the "cid" scheme can only be handled by an MHTML Archive.
-  // Abort the request when there is none.
-  if (!archive_ && resource_request.Url().ProtocolIs(kContentIdScheme))
+  // A main resource request with the "cid" scheme can only be handled by an
+  // MHTML Archive. Abort the request when there is none.
+  // Note: There are some embedders of WebView that are using Content-ID
+  // URLs for sub-resources, even without any MHTMLArchive. Please see

[Torne, 2017/07/14 13:55:47]

Just a note (don't expect you to change this CL for this, but maybe a followup):
while the specific broken cases we've seen in the wild are subresources, in
general WebView embedders can do anything they please with URLs and there's no
reason to assume it's not also used for the main resource somewhere maybe. How
important is it that this check exists at all?

The only URL usage we have actually forbidden in WebView is intercepting the
chrome:// scheme, because the security assumptions around this are too deeply
embedded in chromium to work around.

[arthursonzogni, 2017/07/17 10:58:15]

Thanks for this information.

Without this check, some weird pages caused the renderer to be killed.

What I will probably do in a follow up will be what I did in the first patchset
of https://codereview.chromium.org/2834013002/#ps140001
(i.e. returning true in ShouldMakeNetworkRequestForURL(GURL("cid:xxxx")) and
modify RenderFrameImpl::DecidePolicyForNavigation() appropriately).
It will result in the removal of the part that block Content-ID URLs in the
ResourceFetcher.
I didn't do that right now in order to have a very simple CL that is easy to
merge in M60.

+  // https://crbug.com/739658.
+  if (!archive_ && factory.GetType() == Resource::kMainResource &&
+      resource_request.Url().ProtocolIs(kContentIdScheme)) {
     return nullptr;
+  }
 
   bool is_data_url = resource_request.Url().ProtocolIsData();
   bool is_static_data = is_data_url || substitute_data.IsValid() || archive_;