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

snapshot/minidump/minidump_string_reader.cc

Index: snapshot/minidump/minidump_string_reader.cc
diff --git a/snapshot/minidump/minidump_string_reader.cc b/snapshot/minidump/minidump_string_reader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6ea36089f60c726e2ec8c7a62e7b00a12ca8b16b
--- /dev/null
+++ b/snapshot/minidump/minidump_string_reader.cc
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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.
+
+#include "snapshot/minidump/minidump_string_reader.h"
+
+#include "base/logging.h"
+#include "minidump/minidump_extensions.h"
+
+namespace crashpad {
+namespace internal {
+
+bool ReadMinidumpUTF8String(FileReaderInterface* file_reader,
+                            RVA rva,
+                            std::string* string) {
+  if (rva == 0) {
+    string->clear();
+    return true;
+  }
+
+  if (!file_reader->SeekSet(rva)) {
+    return false;
+  }
+
+  uint32_t string_size;
+  if (!file_reader->ReadExactly(&string_size, sizeof(string_size))) {
+    return false;
+  }
+
+  std::string local_string(string_size, '\0');
+  if (!file_reader->ReadExactly(&local_string[0], string_size)) {
+    return false;
+  }
+
+  string->swap(local_string);
+  return true;
+}
+
+}  // namespace internal
+}  // namespace crashpad