Skeleton of the Safe Browsing Subresource Filter.

components/subresource_filter/content/common/subresource_filter_messages.h

Index: components/subresource_filter/content/common/subresource_filter_messages.h
diff --git a/components/subresource_filter/content/common/subresource_filter_messages.h b/components/subresource_filter/content/common/subresource_filter_messages.h
new file mode 100644
index 0000000000000000000000000000000000000000..7cbcf1a8b95be17a5ba336d2c6bc6d487f997036
--- /dev/null
+++ b/components/subresource_filter/content/common/subresource_filter_messages.h
@@ -0,0 +1,26 @@
+// 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.
+
+// Message definition file, included multiple times, hence no include guard.
+
+#include "components/subresource_filter/core/common/activation_state.h"
+#include "content/public/common/common_param_traits_macros.h"
+#include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_message.h"
+
+#define IPC_MESSAGE_START SubresourceFilterMsgStart
+
+IPC_ENUM_TRAITS_MAX_VALUE(subresource_filter::ActivationState,
+                          subresource_filter::ActivationState::LAST);
+
+// ----------------------------------------------------------------------------
+// Messages sent from the browser to the renderer.
+// ----------------------------------------------------------------------------
+
+// Instructs the renderer to activate subresource filtering for the currently
+// ongoing provisional document load in a frame. The message must arrive after
+// the provisional load starts, but before it is committed on the renderer side.
+// If no message arrives, the default behavior is ActivationState::DISABLED.
+IPC_MESSAGE_ROUTED1(SubresourceFilterAgentMsg_ActivateForProvisionalLoad,
+                    subresource_filter::ActivationState);

[jochen (gone - plz use gerrit), 2016/06/01 15:23:33]

any reason this is not using mojo ipc?

[engedy, 2016/06/01 21:00:44]

Yes. Mojo does not currently provide FIFO ordering between Mojo and legacy IPC
messages [1], and here we need a guarantee that this message arrives to the
renderer before ResourceMsg_DataReceived. Otherwise the provisional might be
committed and subresource loads might already be in flight at the time the
filter is activated.

[1]:
https://groups.google.com/a/chromium.org/d/topic/chromium-mojo/h6L7KSxpl8E/di...