Add ProcessSnapshotMinidump, the beginning of the minidump variant of the Snapshot family

snapshot/minidump/minidump_string_reader.h

Index: snapshot/minidump/minidump_string_reader.h
diff --git a/snapshot/minidump/minidump_string_reader.h b/snapshot/minidump/minidump_string_reader.h
new file mode 100644
index 0000000000000000000000000000000000000000..e5667ec242bc8f53d570179f4eddfeb2f8cb90f7
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+++ b/snapshot/minidump/minidump_string_reader.h
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+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_SNAPSHOT_MINIDUMP_MINIDUMP_STRING_READER_H_
+#define CRASHPAD_SNAPSHOT_MINIDUMP_MINIDUMP_STRING_READER_H_
+
+#include <windows.h>
+#include <dbghelp.h>
+
+#include <string>
+
+#include "util/file/file_reader.h"
+
+namespace crashpad {
+namespace internal {
+
+//! \brief Reads a MinidumpUTF8String from a minidump file at offset \a rva in
+//!     \a file_reader, and returns it in \a string.
+//!
+//! \return `true` on success, with \a string set. `false` on failure, with a
+//!     message logged.
+bool ReadMinidumpUTF8String(FileReaderInterface* file_reader,
+                            RVA rva,
+                            std::string* string);
+
+}  // namespace internal
+}  // namespace crashpad
+
+#endif  // CRASHPAD_SNAPSHOT_MINIDUMP_MINIDUMP_STRING_READER_H_