Implemented GetWindowSnapshot on RenderViewImpl

ui/snapshot/snapshot_export.h

Index: ui/snapshot/snapshot_export.h
diff --git a/ui/snapshot/snapshot_export.h b/ui/snapshot/snapshot_export.h
new file mode 100644
index 0000000000000000000000000000000000000000..9e27370e7a906992641f47062915e1a9588467df
--- /dev/null
+++ b/ui/snapshot/snapshot_export.h
@@ -0,0 +1,32 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_SNAPSHOT_SNAPSHOT_EXPORT_H
+#define UI_SNAPSHOT_SNAPSHOT_EXPORT_H
+
+// Defines SNAPSHOT_EXPORT so that functionality implemented by the snapshot
+// module can be exported to consumers.
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(SNAPSHOT_IMPLEMENTATION)
+#define SNAPSHOT_EXPORT __declspec(dllexport)
+#else
+#define SNAPSHOT_EXPORT __declspec(dllimport)
+#endif  // defined(SNAPSHOT_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(SNAPSHOT_IMPLEMENTATION)
+#define SNAPSHOT_EXPORT __attribute__((visibility("default")))
+#else
+#define SNAPSHOT_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define SNAPSHOT_EXPORT
+#endif
+
+#endif  // UI_SNAPSHOT_SNAPSHOT_EXPORT_H