Add sw support to viewer on Linux.

tools/viewer/sk_app/unix/Window_unix.cpp

Index: tools/viewer/sk_app/unix/Window_unix.cpp
diff --git a/tools/viewer/sk_app/unix/Window_unix.cpp b/tools/viewer/sk_app/unix/Window_unix.cpp
index c4729263eca9a144cc1419e815d45ebb5c0b6f3b..55c27dcb8e2088a93081675bc6254e34ada7b300 100644
--- a/tools/viewer/sk_app/unix/Window_unix.cpp
+++ b/tools/viewer/sk_app/unix/Window_unix.cpp
@@ -14,6 +14,7 @@
 #include "../VulkanWindowContext.h"
 #endif
 #include "Window_unix.h"
+#include "RasterWindowContext_unix.h"
 
 extern "C" {
     #include "keysym2ucs.h"
@@ -283,8 +284,11 @@ bool Window_unix::attach(BackendType attachType, const DisplayParams& params) {
             fWindowContext = VulkanWindowContext::Create((void*)&platformData, params);
             break;
 #endif
+        case kRaster_BackendType:
+            fWindowContext = RasterWindowContext_unix::Create(platformData.fDisplay,

[jvanverth1, 2016/07/19 21:18:11]

Is there a reason you're using RasterWindowContext_unix::Create rather than
RasterWindowContext::Create?

+                                                              platformData.fWindow, params);
+            break;
         case kNativeGL_BackendType:
-        default:
             fWindowContext = GLWindowContext::Create((void*)&platformData, params);
             break;
     }