Add support for EGL on linux

include/gpu/gl/SkNativeGLContext.h

Index: include/gpu/gl/SkNativeGLContext.h
diff --git a/include/gpu/gl/SkNativeGLContext.h b/include/gpu/gl/SkNativeGLContext.h
index 3bb6530c270f0ad717dd53da5f3360f4a6151e3b..93b5b4183ac34794a5cf21c4f288137a346f185c 100644
--- a/include/gpu/gl/SkNativeGLContext.h
+++ b/include/gpu/gl/SkNativeGLContext.h
@@ -35,7 +35,7 @@ static const struct { int major, minor; } gl_versions[] = {
 
 #if defined(SK_BUILD_FOR_MAC)
     #include <OpenGL/OpenGL.h>
-#elif defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_NACL)
+#elif SK_EGL
     #include <GLES2/gl2.h>
     #include <EGL/egl.h>
 #elif defined(SK_BUILD_FOR_UNIX)
@@ -64,7 +64,7 @@ public:
     private:
     #if defined(SK_BUILD_FOR_MAC)
         CGLContextObj fOldCGLContext;
-    #elif defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_NACL)
+    #elif SK_EGL
         EGLContext fOldEGLContext;
         EGLDisplay fOldDisplay;
         EGLSurface fOldSurface;
@@ -88,7 +88,7 @@ protected:
 private:
 #if defined(SK_BUILD_FOR_MAC)
     CGLContextObj fContext;
-#elif defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_NACL)
+#elif SK_EGL
     EGLContext fContext;
     EGLDisplay fDisplay;
     EGLSurface fSurface;