Revert "flat_map: Readd constructors and assignment operator overloads."

This reverts commit 1131840b.

Reason for revert: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89381
got fixed and this change interferes with https://crrev.com/c/2494941.
That change added a new sorted_unique_t constructor tag to
base::flat_tree, but wasn't taking effect for flat_map, since those
constructors were not inherited.


Original change's description:
> flat_map: Readd constructors and assignment operator overloads.
>
> https://chromium-review.googlesource.com/c/chromium/src/+/705955 ("base::flat_map
> was missing defaults for duplication handling") removed them in favor of
> inheriting them from flat_tree.
>
> This can cause problems with GCC due to
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84782, and the build has been
> failing with it since
> https://chromium-review.googlesource.com/1000393 ("Mojo C++ Bindings:
> unordered_map => flat_map") with a message like this:
>
>     gen/mojo/public/interfaces/bindings/tests/test_unions.mojom.cc: In member function ‘void mojo::test::ObjectUnion::set_f_map_int8(const base::flat_map<std::__cxx11::basic_string<char>, signed char>&)’:
>     gen/mojo/public/interfaces/bindings/tests/test_unions.mojom.cc:455:30: error: use of deleted function ‘base::flat_map<std::__cxx11::basic_string<char>, signed char>::flat_map(const base::flat_map<std::__cxx11::basic_string<char>, signed char>&)’
>              std::move(f_map_int8));
>                                   ^
>     In file included from ../../mojo/public/cpp/bindings/clone_traits.h:11:0,
>                      from gen/mojo/public/interfaces/bindings/tests/test_unions.mojom.h:22,
>                      from gen/mojo/public/interfaces/bindings/tests/test_unions.mojom.cc:15:
>     ../../base/containers/flat_map.h:152:7: note: ‘base::flat_map<std::__cxx11::basic_string<char>, signed char>::flat_map(const base::flat_map<std::__cxx11::basic_string<char>, signed char>&)’ is implicitly declared as deleted because ‘base::flat_map<std::__cxx11::basic_string<char>, signed char>’ declares a move constructor or move assignment operator
>      class flat_map : public ::base::internal::flat_tree<
>            ^~~~~~~~
>
> Work around it by replacing the inheritance statements with actual
> constructors and operator=() overloads again. This change does not
> completely revert https://chromium-review.googlesource.com/1000393, as the
> constructors maintain their new signature (so that they look like
> flat_tree's).
>
> Bug: 819294, 837221
> Change-Id: I8f37a2c8aa269b3c1025cdc009518a7709e95947
> Reviewed-on: https://chromium-review.googlesource.com/1038103
> Commit-Queue: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: kylechar <kylechar@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#556168}

TBR=danakj@chromium.org,dcheng@chromium.org,raphael.kubo.da.costa@intel.com,kylechar@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 819294
Bug: 837221
Change-Id: I72915a49981c114f16eaa866de226e9cd242a348
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2526100Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825738}

base/containers/flat_map.h

@@ -205,34 +205,14 @@ class flat_map : public ::base::internal::flat_tree<
   // --------------------------------------------------------------------------
   // Lifetime and assignments.
   //
-  // Note: we could do away with these constructors, destructor and assignment
-  // operator overloads by inheriting |tree|'s, but this breaks the GCC build
-  // due to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84782 (see
-  // https://crbug.com/837221).
-
-  flat_map() = default;
-  explicit flat_map(const Compare& comp);
-
-  template <class InputIterator>
-  flat_map(InputIterator first,
-           InputIterator last,
-           const Compare& comp = Compare());
-
-  flat_map(const flat_map&) = default;
-  flat_map(flat_map&&) noexcept = default;
-
-  flat_map(const container_type& items, const Compare& comp = Compare());
-  flat_map(container_type&& items, const Compare& comp = Compare());
-
-  flat_map(std::initializer_list<value_type> ilist,
-           const Compare& comp = Compare());
-
-  ~flat_map() = default;
+  // Note: we explicitly bring operator= in because otherwise
+  //   flat_map<...> x;
+  //   x = {...};
+  // Would first create a flat_map and then move assign it. This most likely
+  // would be optimized away but still affects our debug builds.
 
-  flat_map& operator=(const flat_map&) = default;
-  flat_map& operator=(flat_map&&) noexcept = default;
-  // Takes the first if there are duplicates in the initializer list.
-  flat_map& operator=(std::initializer_list<value_type> ilist);
+  using tree::tree;
+  using tree::operator=;
 
   // Out-of-bound calls to at() will CHECK.
   template <class K>
@@ -275,52 +255,6 @@ class flat_map : public ::base::internal::flat_tree<
   friend void swap(flat_map& lhs, flat_map& rhs) noexcept { lhs.swap(rhs); }
 };
 
-// ----------------------------------------------------------------------------
-// Lifetime.
-
-template <class Key, class Mapped, class Compare, class Container>
-flat_map<Key, Mapped, Compare, Container>::flat_map(const Compare& comp)
-    : tree(comp) {}
-
-template <class Key, class Mapped, class Compare, class Container>
-template <class InputIterator>
-flat_map<Key, Mapped, Compare, Container>::flat_map(InputIterator first,
-                                                    InputIterator last,
-                                                    const Compare& comp)
-    : tree(first, last, comp) {}
-
-template <class Key, class Mapped, class Compare, class Container>
-flat_map<Key, Mapped, Compare, Container>::flat_map(const container_type& items,
-                                                    const Compare& comp)
-    : tree(items, comp) {}
-
-template <class Key, class Mapped, class Compare, class Container>
-flat_map<Key, Mapped, Compare, Container>::flat_map(container_type&& items,
-                                                    const Compare& comp)
-    : tree(std::move(items), comp) {}
-
-template <class Key, class Mapped, class Compare, class Container>
-flat_map<Key, Mapped, Compare, Container>::flat_map(
-    std::initializer_list<value_type> ilist,
-    const Compare& comp)
-    : flat_map(std::begin(ilist), std::end(ilist), comp) {}
-
-// ----------------------------------------------------------------------------
-// Assignments.
-
-template <class Key, class Mapped, class Compare, class Container>
-auto flat_map<Key, Mapped, Compare, Container>::operator=(
-    std::initializer_list<value_type> ilist) -> flat_map& {
-  // When https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84782 gets fixed, we
-  // need to remember to inherit tree::operator= to prevent
-  //   flat_map<...> x;
-  //   x = {...};
-  // from first creating a flat_map and then move assigning it. This most
-  // likely would be optimized away but still affects our debug builds.
-  tree::operator=(ilist);
-  return *this;
-}
-
 // ----------------------------------------------------------------------------
 // Lookups.
 

chrome/services/cups_proxy/ipp_validator_unittest.cc

@@ -97,7 +97,8 @@ IppRequestPtr GetBasicIppRequest() {
   ret->http_version = "HTTP/1.1";
 
   // Map of Http headers.
-  ret->headers = std::vector<ipp_converter::HttpHeader>{
+  ret->headers = base::flat_map<ipp_converter::HttpHeader::first_type,
+                                ipp_converter::HttpHeader::second_type>{
       {"Content-Length", "72"},
       {"Content-Type", "application/ipp"},
       {"Date", "Thu, 04 Oct 2018 20:25:59 GMT"},

chrome/services/ipp_parser/ipp_parser.cc

@@ -10,6 +10,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/containers/flat_map.h"
 #include "base/optional.h"
 #include "chrome/services/cups_proxy/public/cpp/type_conversions.h"
 #include "chrome/services/ipp_parser/public/cpp/ipp_converter.h"
@@ -181,7 +182,8 @@ void IppParser::ParseIpp(const std::vector<uint8_t>& to_parse,
   parsed_request->endpoint = request_line_terms[1];
   parsed_request->http_version = request_line_terms[2];
 
-  parsed_request->headers = std::move(*headers);
+  parsed_request->headers =
+      base::flat_map<std::string, std::string>(std::move(*headers));
   parsed_request->ipp = std::move(ipp_message);
   parsed_request->data = std::move(ipp_data);
 

content/common/fetch/fetch_api_request_proto.cc

@@ -48,8 +48,8 @@ blink::mojom::FetchAPIRequestPtr DeserializeFetchRequestFromString(
   request_ptr->frame_type = blink::mojom::RequestContextFrameType::kNone;
   request_ptr->url = GURL(request_proto.url());
   request_ptr->method = request_proto.method();
-  request_ptr->headers = {request_proto.headers().begin(),
-                          request_proto.headers().end()};
+  request_ptr->headers = blink::FetchAPIRequestHeadersMap(
+      request_proto.headers().begin(), request_proto.headers().end());
   request_ptr->referrer = blink::mojom::Referrer::New(
       GURL(request_proto.referrer().url()),
 

content/public/test/test_utils.cc

@@ -117,7 +117,7 @@ blink::mojom::FetchAPIRequestPtr CreateFetchAPIRequest(
   auto request = blink::mojom::FetchAPIRequest::New();
   request->url = url;
   request->method = method;
-  request->headers = {headers.begin(), headers.end()};
+  request->headers = headers;
   request->referrer = std::move(referrer);
   request->is_reload = is_reload;
   return request;