Move ImageFetcher to its own target.

ios/chrome/browser/net/BUILD.gn

Index: ios/chrome/browser/net/BUILD.gn
diff --git a/ios/chrome/browser/net/BUILD.gn b/ios/chrome/browser/net/BUILD.gn
index 4b26d7f72c7596c18f820d93b31ee35db071b584..908ae7ee8d765075cfb760b743fcccbb94c3d4f6 100644
--- a/ios/chrome/browser/net/BUILD.gn
+++ b/ios/chrome/browser/net/BUILD.gn
@@ -36,6 +36,7 @@ source_set("net") {
     "//base",
     "//components/component_updater",
     "//components/content_settings/core/browser",
+    "//components/image_fetcher/ios",
     "//components/pref_registry",
     "//components/prefs",
     "//components/proxy_config",
@@ -43,7 +44,6 @@ source_set("net") {
     "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/browsing_data",
-    "//ios/chrome/browser/webp_transcode",
     "//ios/net",
     "//ios/web",
     "//net",
@@ -72,7 +72,6 @@ source_set("unit_tests") {
   testonly = true
   sources = [
     "cookie_util_unittest.mm",
-    "image_fetcher_unittest.mm",
     "metrics_network_client_unittest.mm",
     "retryable_url_fetcher_unittest.mm",
   ]