Add OpenGL context to Viewer.

tools/viewer/sk_app/Window.h

Index: tools/viewer/sk_app/Window.h
diff --git a/tools/viewer/sk_app/Window.h b/tools/viewer/sk_app/Window.h
index f233f131a5eb15f1ce6bf5865502c3a339291197..5b41f87f074afd26ee28e98f410f5aa1ca20bd99 100644
--- a/tools/viewer/sk_app/Window.h
+++ b/tools/viewer/sk_app/Window.h
@@ -32,12 +32,17 @@ public:
     virtual bool supportsContentRect() const { return false; }
     virtual SkRect getContentRect() { return SkRect::MakeEmpty(); }
 
-    enum BackEndType {
+    enum BackendType {
         kNativeGL_BackendType,
-        kVulkan_BackendType
+        kVulkan_BackendType,
+
+        kLast_BackendType = kVulkan_BackendType
+    };
+    enum {
+        kBackendTypeCount = kLast_BackendType + 1

[Brian Osman, 2016/05/17 17:32:11]

Is this used anywhere?

[jvanverth1, 2016/05/17 17:59:50]

It's used for the array of strings in Viewer.cpp.

     };
 
-    virtual bool attach(BackEndType attachType,  const DisplayParams& params) = 0;
+    virtual bool attach(BackendType attachType,  const DisplayParams& params) = 0;
     void detach();
 
     // input handling