win: Implement exception snapshot

snapshot/win/cpu_context_win.h

 // 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 "test/paths.h"
+#ifndef CRASHPAD_SNAPSHOT_WIN_CPU_CONTEXT_WIN_H_

[Mark Mentovai, 2015/08/18 16:17:19]

Can you do your next upload with --no-find-copies?

[scottmg, 2015/08/18 16:56:00]

Will do.

+#define CRASHPAD_SNAPSHOT_WIN_CPU_CONTEXT_WIN_H_
 
 #include <windows.h>
 
 namespace crashpad {
-namespace test {
 
-// static
-base::FilePath Paths::Executable() {
-  wchar_t executable_path[_MAX_PATH];
-  GetModuleFileName(nullptr, executable_path, sizeof(executable_path));
-  return base::FilePath(executable_path);
-}
+struct CPUContextX86;
+struct CPUContextX86_64;
 
-}  // namespace test
+//! \brief Initializes a CPUContextX86 structure from native context structures

[Mark Mentovai, 2015/08/18 16:17:19]

Singular “a native context structure” or “a native `CONTEXT` structure”. Same
for the other function.

[scottmg, 2015/08/18 16:56:00]

Done.

+//!     on Windows.
+void InitializeX86Context(const CONTEXT& context, CPUContextX86* out);

[Mark Mentovai, 2015/08/18 16:17:19]

Because CONTEXT is one structure that’s CPU-specific, I don’t know if it makes
sense to have all of the various Initialize variants declared. But I don’t yet
see from the .cc file what the plan is to do cross-arch context initialization.
(Maybe there’s a WoW function to help, or maybe you need to declare the
other-arch CONTEXT yourself?)

[scottmg, 2015/08/18 16:56:00]

Yes, you're right. I'm not sure what's the best solution.

On x64 WOW64_CONTEXT matches x86 CONTEXT, so I #ifdef'd them like that for now.

+
+//! \brief Initializes a CPUContextX86_64 structure from native context
+//!     structures on Windows.
+void InitializeX64Context(const CONTEXT& context, CPUContextX86_64* out);
+
 }  // namespace crashpad
+
+#endif  // CRASHPAD_SNAPSHOT_WIN_CPU_CONTEXT_WIN_H_