From 130ad75c1b9408a91a8f86c320240e4137f35143 Mon Sep 17 00:00:00 2001
From: Mounir Lamouri <mlamouri@chromium.org>
Date: Fri, 13 Oct 2017 17:07:15 +0000
Subject: [PATCH] Export CanonOutputT template instantiations to avoid double
 definition.

The double instantiations seem to happen because of virtual methods. If
the class could lose be non-virtual, this could be fixed. However, this
is blocking another CL and this fix is the optimal one with regards to
time constraints.

Bug: 747081
Change-Id: I5c2d2cc7a9e49266b25d2cd3d9835d0647e5438a
Reviewed-on: https://chromium-review.googlesource.com/579211
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508734}
---
 base/BUILD.gn                   |  1 +
 {ipc => base}/export_template.h |  6 +++---
 ipc/BUILD.gn                    |  1 -
 ipc/ipc_message_macros.h        |  2 +-
 url/BUILD.gn                    |  1 +
 url/url_canon.cc                | 12 ++++++++++++
 url/url_canon.h                 |  6 ++++++
 7 files changed, 24 insertions(+), 5 deletions(-)
 rename {ipc => base}/export_template.h (98%)
 create mode 100644 url/url_canon.cc

diff --git a/base/BUILD.gn b/base/BUILD.gn
index 78c04dcfce80a7..a843c7ffbae007 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -294,6 +294,7 @@ component("base") {
     "environment.cc",
     "environment.h",
     "event_types.h",
+    "export_template.h",
     "feature_list.cc",
     "feature_list.h",
     "file_descriptor_posix.h",
diff --git a/ipc/export_template.h b/base/export_template.h
similarity index 98%
rename from ipc/export_template.h
rename to base/export_template.h
index e743e1936f7a5a..aac8b7c7f122a0 100644
--- a/ipc/export_template.h
+++ b/base/export_template.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef IPC_EXPORT_TEMPLATE_H_
-#define IPC_EXPORT_TEMPLATE_H_
+#ifndef BASE_EXPORT_TEMPLATE_H_
+#define BASE_EXPORT_TEMPLATE_H_
 
 // Synopsis
 //
@@ -160,4 +160,4 @@ EXPORT_TEMPLATE_TEST(DEFAULT, __declspec(dllimport));
 #undef EXPORT_TEMPLATE_TEST_DEFAULT_DEFAULT
 #undef EXPORT_TEMPLATE_TEST_MSVC_HACK_MSVC_HACK
 
-#endif  // IPC_EXPORT_TEMPLATE_H_
+#endif  // BASE_EXPORT_TEMPLATE_H_
diff --git a/ipc/BUILD.gn b/ipc/BUILD.gn
index a63907022b583d..3d020c55f01846 100644
--- a/ipc/BUILD.gn
+++ b/ipc/BUILD.gn
@@ -22,7 +22,6 @@ buildflag_header("ipc_features") {
 
 component("ipc") {
   sources = [
-    "export_template.h",
     "ipc_channel.cc",
     "ipc_channel.h",
     "ipc_channel_common.cc",
diff --git a/ipc/ipc_message_macros.h b/ipc/ipc_message_macros.h
index ccb7ce4a17a046..2cab6fb258b8be 100644
--- a/ipc/ipc_message_macros.h
+++ b/ipc/ipc_message_macros.h
@@ -201,7 +201,7 @@
 
 #include <tuple>
 
-#include "ipc/export_template.h"
+#include "base/export_template.h"
 #include "ipc/ipc_message_templates.h"
 #include "ipc/ipc_message_utils.h"
 #include "ipc/param_traits_macros.h"
diff --git a/url/BUILD.gn b/url/BUILD.gn
index 82eb115ae66633..d33801bc8ae857 100644
--- a/url/BUILD.gn
+++ b/url/BUILD.gn
@@ -25,6 +25,7 @@ component("url") {
     "scheme_host_port.h",
     "third_party/mozilla/url_parse.cc",
     "third_party/mozilla/url_parse.h",
+    "url_canon.cc",
     "url_canon.h",
     "url_canon_etc.cc",
     "url_canon_filesystemurl.cc",
diff --git a/url/url_canon.cc b/url/url_canon.cc
new file mode 100644
index 00000000000000..d51a3179e108e5
--- /dev/null
+++ b/url/url_canon.cc
@@ -0,0 +1,12 @@
+// Copyright 2017 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 "url/url_canon.h"
+
+namespace url {
+
+template class EXPORT_TEMPLATE_DEFINE(URL_EXPORT) CanonOutputT<char>;
+template class EXPORT_TEMPLATE_DEFINE(URL_EXPORT) CanonOutputT<base::char16>;
+
+}  // namespace url
diff --git a/url/url_canon.h b/url/url_canon.h
index 887150b0591791..ede62d327bd762 100644
--- a/url/url_canon.h
+++ b/url/url_canon.h
@@ -8,6 +8,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "base/export_template.h"
 #include "base/strings/string16.h"
 #include "url/third_party/mozilla/url_parse.h"
 #include "url/url_export.h"
@@ -174,6 +175,11 @@ class RawCanonOutputT : public CanonOutputT<T> {
   T fixed_buffer_[fixed_capacity];
 };
 
+// Explicitely instantiate commonly used instatiations.
+extern template class EXPORT_TEMPLATE_DECLARE(URL_EXPORT) CanonOutputT<char>;
+extern template class EXPORT_TEMPLATE_DECLARE(URL_EXPORT)
+    CanonOutputT<base::char16>;
+
 // Normally, all canonicalization output is in narrow characters. We support
 // the templates so it can also be used internally if a wide buffer is
 // required.