Use gdb::function_view in iterate_over_symtabs & co

I wanted to pass a lambda to iterate_over_symtabs (see following
patch), so I converted it to function_view, and then the rest is
cascaded from that.

This gets rid of a bunch of single-use callback functions and
corresponding manually managed callback capture types
(add_partial_datum, search_symbols_data, etc.) in favor of letting the
compiler generate them for us by using lambdas with a capture.  In a
couple cases, it was more natural to convert the existing function
callbacks to function objects (i.e., operator(), e.g.,
decode_compound_collector).

gdb/ChangeLog:
2017-02-23  Pedro Alves  <palves@redhat.com>

	* ada-lang.c: Include "common/function-view.h".
	(ada_iterate_over_symbols): Adjust to use function_view as
	callback type.
	(struct add_partial_datum, ada_complete_symbol_matcher): Delete.
	(ada_make_symbol_completion_list): Use a lambda.
	(ada_exc_search_name_matches): Delete.
	(name_matches_regex): New.
	(ada_add_global_exceptions): Use a lambda and name_matches_regex.
	* compile/compile-c-support.c: Include "common/function-view.h".
	(print_one_macro): Change prototype to accept a ui_file pointer.
	(write_macro_definitions): Use a lambda.
	* dwarf2read.c: Include "common/function-view.h".
	(dw2_map_expand_apply, dw2_map_symtabs_matching_filename)
	(dw2_expand_symtabs_matching): Adjust to use function_view as
	callback type.
	* language.h: Include "common/function-view.h".
	(struct language_defn) <la_iterate_over_symbols>: Adjust to use
	function_view as callback type.
	(LA_ITERATE_OVER_SYMBOLS): Remove DATA parameter.
	* linespec.c: Include "common/function-view.h".
	(collect_info::add_symbol): New method.
	(struct symbol_and_data_callback, iterate_inline_only, struct
	symbol_matcher_data, iterate_name_matcher): Delete.
	(iterate_over_all_matching_symtabs): Adjust to use function_view
	as callback type and lambdas.
	(iterate_over_file_blocks): Adjust to use function_view as
	callback type.
	(decode_compound_collector): Now a class with private fields.
	(decode_compound_collector::release_symbols): New method.
	(collect_one_symbol): Rename to...
	(decode_compound_collector::operator()): ... this and adjust.
	(lookup_prefix_sym): decode_compound_collector construction bits
	move to decode_compound_collector ctor.  Pass the
	decode_compound_collector object directly as callback.  Remove
	cleanups and use decode_compound_collector::release_symbols
	instead.
	(symtab_collector): Now a class with private fields.
	(symtab_collector::release_symtabs): New method.
	(add_symtabs_to_list): Rename to...
	(symtab_collector::operator()): ... this and adjust.
	(collect_symtabs_from_filename): symtab_collector construction
	bits move to symtab_collector ctor.  Pass the symtab_collector
	object directly as callback.  Remove cleanups and use
	symtab_collector::release_symtabs instead.
	(collect_symbols): Delete.
	(add_matching_symbols_to_info): Use lambdas.
	* macrocmd.c (print_macro_callback): Delete.
	(info_macro_command): Use a lambda.
	(info_macros_command): Pass print_macro_definition as callable
	directly.
	(print_one_macro): Remove 'ignore' parameter.
	(macro_list_command): Adjust.
	* macrotab.c (macro_for_each_data::fn): Now a function_view.
	(macro_for_each_data::user_data): Delete field.
	(foreach_macro): Adjust to call the function_view.
	(macro_for_each): Adjust to use function_view as callback type.
	(foreach_macro_in_scope): Adjust to call the function_view.
	(macro_for_each_in_scope): Adjust to use function_view as callback
	type.
	* macrotab.h: Include "common/function-view.h".
	(macro_callback_fn): Declare a prototype instead of a pointer.
	Remove "user_data" parameter.
	(macro_for_each, macro_for_each_in_scope): Adjust to use
	function_view as callback type.
	* psymtab.c (partial_map_expand_apply)
	(psym_map_symtabs_matching_filename, recursively_search_psymtabs):
	Adjust to use function_view as callback type and to return bool.
	(psym_expand_symtabs_matching): Adjust to use function_view as
	callback types.
	* symfile-debug.c (debug_qf_map_symtabs_matching_filename): Adjust
	to use function_view as callback type and to return bool.
	(debug_qf_expand_symtabs_matching): Adjust to use function_view as
	callback types.
	* symfile.c (expand_symtabs_matching): Adjust to use function_view
	as callback types.
	* symfile.h: Include "common/function-view.h".
	(expand_symtabs_file_matcher_ftype)
	(expand_symtabs_symbol_matcher_ftype)
	(expand_symtabs_exp_notify_ftype): Remove "data" parameter and
	return bool.
	(quick_symbol_functions::map_symtabs_matching_filename)
	(quick_symbol_functions::expand_symtabs_matching): Adjust to use
	function_view as callback type and return bool.
	(expand_symtabs_matching): Adjust to use function_view as callback
	type.
	(maintenance_expand_name_matcher)
	(maintenance_expand_file_matcher): Delete.
	(maintenance_expand_symtabs): Use lambdas.
	* symtab.c (iterate_over_some_symtabs): Adjust to use
	function_view as callback types and return bool.
	(iterate_over_symtabs): Likewise.  Use unique_xmalloc_ptr instead
	of a cleanup.
	(lookup_symtab_callback): Delete.
	(lookup_symtab): Use a lambda.
	(iterate_over_symbols): Adjust to use function_view as callback
	type.
	(struct search_symbols_data, search_symbols_file_matches)
	(search_symbols_name_matches): Delete.
	(search_symbols): Use a pair of lambdas.
	(struct add_name_data, add_macro_name, symbol_completion_matcher)
	(symtab_expansion_callback): Delete.
	(default_make_symbol_completion_list_break_on_1): Use lambdas.
	* symtab.h: Include "common/function-view.h".
	(iterate_over_some_symtabs): Adjust to use function_view as
	callback type and return bool.
	(iterate_over_symtabs): Adjust to use function_view as callback
	type.
	(symbol_found_callback_ftype): Remove 'data' parameter and return
	bool.
	(iterate_over_symbols): Adjust to use function_view as callback
	type.

gdb/symtab.h

@@ -24,6 +24,7 @@
 #include "gdb_vecs.h"
 #include "gdbtypes.h"
 #include "common/enum-flags.h"
+#include "common/function-view.h"
 
 /* Opaque declarations.  */
 struct ui_file;
@@ -1607,35 +1608,29 @@ int compare_filenames_for_search (const char *filename,
 int compare_glob_filenames_for_search (const char *filename,
 				       const char *search_name);
 
-int iterate_over_some_symtabs (const char *name,
-			       const char *real_path,
-			       int (*callback) (struct symtab *symtab,
-						void *data),
-			       void *data,
-			       struct compunit_symtab *first,
-			       struct compunit_symtab *after_last);
+bool iterate_over_some_symtabs (const char *name,
+				const char *real_path,
+				struct compunit_symtab *first,
+				struct compunit_symtab *after_last,
+				gdb::function_view<bool (symtab *)> callback);
 
 void iterate_over_symtabs (const char *name,
-			   int (*callback) (struct symtab *symtab,
-					    void *data),
-			   void *data);
+			   gdb::function_view<bool (symtab *)> callback);
+
 
 VEC (CORE_ADDR) *find_pcs_for_symtab_line (struct symtab *symtab, int line,
 					   struct linetable_entry **best_entry);
 
-/* Callback for LA_ITERATE_OVER_SYMBOLS.  The callback will be called
-   once per matching symbol SYM, with DATA being the argument of the
-   same name that was passed to LA_ITERATE_OVER_SYMBOLS.  The callback
-   should return nonzero to indicate that LA_ITERATE_OVER_SYMBOLS
-   should continue iterating, or zero to indicate that the iteration
-   should end.  */
+/* Prototype for callbacks for LA_ITERATE_OVER_SYMBOLS.  The callback
+   is called once per matching symbol SYM.  The callback should return
+   true to indicate that LA_ITERATE_OVER_SYMBOLS should continue
+   iterating, or false to indicate that the iteration should end.  */
 
-typedef int (symbol_found_callback_ftype) (struct symbol *sym, void *data);
+typedef bool (symbol_found_callback_ftype) (symbol *sym);
 
 void iterate_over_symbols (const struct block *block, const char *name,
 			   const domain_enum domain,
-			   symbol_found_callback_ftype *callback,
-			   void *data);
+			   gdb::function_view<symbol_found_callback_ftype> callback);
 
 /* Storage type used by demangle_for_lookup.  demangle_for_lookup
    either returns a const char * pointer that points to either of the