Use flatpak-spawn to run Google Chrome

This allows us to make a self-contained extra-data flatpak that does
not need to rely on anything on the host to work.

com.google.Chrome.json

@@ -3,7 +3,10 @@
     "runtime": "org.freedesktop.Platform",
     "runtime-version": "1.6",
     "sdk": "org.freedesktop.Sdk",
-    "command": "/app/bin/eos-google-chrome-app",
+    "command": "google-chrome-launcher",
+    "finish-args": [
+        "--talk-name=org.freedesktop.Flatpak"
+    ],
     "cleanup": [
         "/etc",
         "/include",
@@ -22,7 +25,7 @@
             "sources": [
                 {
                     "type": "file",
-                    "path": "eos-google-chrome-app"
+                    "path": "google-chrome-launcher"
                 },
                 {
                     "type": "file",
@@ -47,7 +50,7 @@
             ],
             "build-commands": [
                 "install -d /app/bin",
-                "install eos-google-chrome-app /app/bin/eos-google-chrome-app",
+                "install google-chrome-launcher /app/bin/google-chrome-launcher",
 
                 "install -d /app/share/appdata",
                 "install -m644 com.google.Chrome.appdata.xml /app/share/appdata/com.google.Chrome.appdata.xml",

google-chrome-launcher

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+chrome_flatpak_dir=`flatpak-spawn --host flatpak info -l com.google.Chrome`
+chrome_binary=${chrome_flatpak_dir}/files/extra/opt/google/chrome/google-chrome
+
+exec flatpak-spawn --host --env=LD_LIBRARY_PATH=${chrome_flatpak_dir}/files/lib ${chrome_binary}