Add sRGB mode toggle to Viewer.

tools/viewer/sk_app/DisplayParams.h

Index: tools/viewer/sk_app/DisplayParams.h
diff --git a/tools/viewer/sk_app/DisplayParams.h b/tools/viewer/sk_app/DisplayParams.h
new file mode 100644
index 0000000000000000000000000000000000000000..836b02ec9217604595fa0230e6989fcc7f98116d
--- /dev/null
+++ b/tools/viewer/sk_app/DisplayParams.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef DisplayParams_DEFINED
+#define DisplayParams_DEFINED
+
+#include "SkImageInfo.h"
+
+namespace sk_app {
+
+struct DisplayParams {
+    DisplayParams()
+        : fColorType(kN32_SkColorType)
+        , fProfileType(kLinear_SkColorProfileType)
+        , fMSAASampleCount(0) {}
+
+    SkColorType fColorType;
+    SkColorProfileType fProfileType;
+    int fMSAASampleCount;
+};
+
+}   // namespace sk_app
+
+#endif