[shotwell] flatpak: Build webp

[Jens Georg <jensgeorg src gnome org>]

commit d1d82f33266d444e2e343ef4514a2a59d8b23007
Author: Jens Georg <mail jensge org>
Date:   Tue Sep 11 23:23:49 2018 +0200

    flatpak: Build webp

 flatpak/org.gnome.Shotwell.json | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
---
diff --git a/flatpak/org.gnome.Shotwell.json b/flatpak/org.gnome.Shotwell.json
index 5949b3a2..27f3772e 100644
--- a/flatpak/org.gnome.Shotwell.json
+++ b/flatpak/org.gnome.Shotwell.json
@@ -151,6 +151,21 @@
                 }
             ]
         },
+
+        {
+            "name": "webp",
+            "buildsystem" : "cmake",
+            "builddir" : true,
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://chromium.googlesource.com/webm/libwebp";,
+                    "branch": "1.0.0",
+                    "commit" : "0b271f10c428b59d20a4415247e228f31e0030e4"
+                }
+            ]
+        },
+
         {
             "name": "shotwell",
             "buildsystem": "meson",