Add the Snapshot interface

snapshot/cpu_context.cc

+// 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.
+
+#include "snapshot/cpu_context.h"
+
+#include "base/logging.h"
+
+namespace crashpad {
+
+uint64_t CPUContext::InstructionPointer() const {
+  switch (architecture) {
+    case kCPUArchitectureX86:
+      return x86->eip;
+    case kCPUArchitectureX86_64:
+      return x86_64->rip;
+    default:
+      NOTREACHED();
+      return -1;
+  }
+}
+
+}  // namespace crashpad