Remove dependencies on Skia and the prebuilt network library

Author: abarth

build/module_args/mojo.gni

@@ -13,4 +13,4 @@ mojo_build_mojo_shell_from_source = true
 
 # To build the network service from source, set this variable to true. To use
 # the prebuilt network service, omit this variable or set it to false.
-mojo_build_network_service_from_source = false
+mojo_build_network_service_from_source = true

skia/BUILD.gn

@@ -625,7 +625,6 @@ test("skia_unittests") {
     ":skia",
     "//base",
     "//base/test:run_all_unittests",
-    "//cc:test_support",  # TODO: Fix this test to not depend on cc.
     "//testing/gtest",
     "//ui/gfx",
     "//ui/gfx/geometry",

ui/base/BUILD.gn

@@ -58,7 +58,6 @@ component("base") {
   if (is_android) {
     deps += [
       ":ui_base_jni_headers",
-      "//cc",
     ]
 
     libs += [ "jnigraphics" ]