Introduces a new MHTML generation parameter specifying different behvaior for cache-control headers.

content/public/common/mhtml_generation.h

+// Copyright 2016 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.
+
+#ifndef CONTENT_PUBLIC_COMMON_MHTML_GENERATION_H_
+#define CONTENT_PUBLIC_COMMON_MHTML_GENERATION_H_
+
+#include "base/files/file_path.h"
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/web/WebFrameSerializer.h"

[Łukasz Anforowicz, 2016/05/12 18:56:49]

content/common/DEPS says: No inclusion of WebKit from the browser, other than
strictly enum/POD, header-only types, and some selected common code. 
WebFrameSerializer.h doesn't match this description.

I think either 1) the enums need to be moved to a separate header under
third_party/WebKit/public/web or 2) you need separate enums for content-layer (+
static_asserts somewhere that values are the same as in WebKit counterparts -
similar to third_party/WebKit/Source/web/AssertMatchingEnums.cpp?).

[dewittj, 2016/05/12 22:58:01]

I actually did both.  WDYT about how this looks?

[Łukasz Anforowicz, 2016/05/12 23:56:27]

Looks good - thanks.

+
+namespace content {
+
+using WebFrameSerializer = blink::WebFrameSerializer;
+
+// Options for changing serialization behavior based on the CacheControl header
+// of each subresource.
+enum class MHTMLCacheControlPolicy {
+  IGNORE = WebFrameSerializer::CacheControlPolicyIgnore,
+  FAIL_FOR_NO_STORE_MAIN_FRAME =
+      WebFrameSerializer::CacheControlPolicyFailForNoStoreMainFrame,
+
+  // |LAST| is used in content/common/media/midi_messages.h with

[Łukasz Anforowicz, 2016/05/12 18:56:49]

Copy&paste issue - did you mean
content/public/common/common_param_traits_macros.h?

[dewittj, 2016/05/12 22:58:01]

Done.

+  // IPC_ENUM_TRAITS_MAX_VALUE macro. Keep the value up to date. Otherwise
+  // a new value can not be passed to the renderer.
+  LAST = FAIL_FOR_NO_STORE_MAIN_FRAME
+};
+
+enum class MHTMLSerializationResult {

[Łukasz Anforowicz, 2016/05/12 18:56:49]

I didn't see a place where this enum is used in //content's public API - I think
the highest this enum is used in the layering stack is
//content/browser/download/mhtml_generation_manager.h.  Did I miss anything? 
Can we hide this enum away from //content's public API?

[dewittj, 2016/05/12 22:58:01]

I just got rid of the result since we are not using it yet; that will come in a
later CL if we end up needing for offline pages.

[Łukasz Anforowicz, 2016/05/12 23:56:27]

Acknowledged.

+  OK,
+  FILE_WRITE_FAILED_IN_HEADER,
+  FILE_WRITE_FAILED_IN_PARTS_GEN,
+  FILE_WRITE_FAILED_IN_FOOTER,

[Łukasz Anforowicz, 2016/05/12 18:56:49]

Is there an existing code that needs to distinguish the 3 cases?  Or can this be
collapsed to a single FILE_WRITE_FAILED?  AFAICT we only really distinguish
between OK and not-OK (in MHTMLGenerationManager::OnSerializeAsMHTMLResponse at
https://codereview.chromium.org/1947263004/patch/250001/260005)

[dewittj, 2016/05/12 22:58:01]

obsolete.

[Łukasz Anforowicz, 2016/05/12 23:56:27]

Acknowledged.

+  NO_STORE_MAIN_FRAME,
+
+  // |LAST| is used in content/common/media/midi_messages.h with
+  // IPC_ENUM_TRAITS_MAX_VALUE macro. Keep the value up to date. Otherwise
+  // a new value can not be passed to the renderer.
+  LAST = NO_STORE_MAIN_FRAME
+};
+
+struct CONTENT_EXPORT MHTMLGenerationParams {
+  MHTMLGenerationParams(const base::FilePath& file_path);
+  ~MHTMLGenerationParams() = default;
+
+  // The file that will contain the generated MHTML.
+  base::FilePath file_path;
+
+  // Uses Content-Transfer-Encoding: binary when encoding.  See
+  // https://tools.ietf.org/html/rfc2045 for details about
+  // Content-Transfer-Encoding.
+  bool use_binary_encoding = false;
+
+  // By default, MHTML includes all subresources.  This flag can be used to
+  // cause the generator to fail or silently ignore resources if the
+  // Cache-Control header is used.
+  MHTMLCacheControlPolicy cache_control_policy =
+      MHTMLCacheControlPolicy::IGNORE;
+};
+
+namespace mhtml {
+
+blink::WebFrameSerializer::CacheControlPolicy toCacheControlPolicy(

[Łukasz Anforowicz, 2016/05/12 18:56:49]

Can this be hidden away from //content's public API surface?  Does the embedded
of //content ever want/can access Blink layer?

[dewittj, 2016/05/12 22:58:01]

Done.

+    MHTMLCacheControlPolicy mhtml_policy);
+
+}  // namespace mhtml
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_COMMON_MHTML_GENERATION__