Add MinidumpCrashpadInfoWriter::InitializeFromSnapshot() and its test

minidump/minidump_crashpad_info_writer.h

 // Copyright 2014 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_MINIDUMP_MINIDUMP_CRASHPAD_INFO_WRITER_H_
 #define CRASHPAD_MINIDUMP_MINIDUMP_CRASHPAD_INFO_WRITER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "minidump/minidump_extensions.h"
 #include "minidump/minidump_stream_writer.h"
 
 namespace crashpad {
 
 class MinidumpModuleCrashpadInfoListWriter;
+class ProcessSnapshot;
 
 //! \brief The writer for a MinidumpCrashpadInfo stream in a minidump file.
 class MinidumpCrashpadInfoWriter final : public internal::MinidumpStreamWriter {
  public:
   MinidumpCrashpadInfoWriter();
   ~MinidumpCrashpadInfoWriter() override;
 
+  //! \brief Initializes MinidumpCrashpadInfo based on \a process_snapshot.
+  //!
+  //! This method may add additional structures to the minidump file as children
+  //! of the MinidumpCrashpadInfo stream. To do so, it may obtain other
+  //! snapshot information from \a process_snapshot, such as a list of
+  //! ModuleSnapshot objects used to initialize
+  //! MinidumpCrashpadInfo::module_list. Only data that is considered useful
+  //! will be included. For module information, usefulness is determined by
+  //! MinidumpModuleCrashpadInfoListWriter::IsUseful().
+  //!
+  //! \param[in] process_snapshot The process snapshot to use as source data.
+  //!
+  //! \note Valid in #kStateMutable. No mutator methods may be called before
+  //!     this method, and it is not normally necessary to call any mutator
+  //!     methods after this method.
+  void InitializeFromSnapshot(const ProcessSnapshot* process_snapshot);
+
   //! \brief Arranges for MinidumpCrashpadInfo::module_list to point to the
   //!     MinidumpModuleCrashpadInfoList object to be written by \a
   //!     module_list.
   //!
   //! This object takes ownership of \a module_list and becomes its parent in
   //! the overall tree of internal::MinidumpWritable objects.
   //!
   //! \note Valid in #kStateMutable.
   void SetModuleList(
       scoped_ptr<MinidumpModuleCrashpadInfoListWriter> module_list);
 
+  //! \brief Determines whether the object is useful.
+  //!
+  //! A useful object is one that carries data that makes a meaningful
+  //! contribution to a minidump file. An object carrying children would be
+  //! considered useful.
+  //!
+  //! \return `true` if the object is useful, `false` otherwise.
+  bool IsUseful() const;
+
  protected:
   // MinidumpWritable:
   bool Freeze() override;
   size_t SizeOfObject() override;
   std::vector<MinidumpWritable*> Children() override;
   bool WriteObject(FileWriterInterface* file_writer) override;
 
   // MinidumpStreamWriter:
   MinidumpStreamType StreamType() const override;
 
  private:
   MinidumpCrashpadInfo crashpad_info_;
   scoped_ptr<MinidumpModuleCrashpadInfoListWriter> module_list_;
 
   DISALLOW_COPY_AND_ASSIGN(MinidumpCrashpadInfoWriter);
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_MINIDUMP_MINIDUMP_CRASHPAD_INFO_WRITER_H_