[ios] Separate the test sink into a separate library

- Do not build all the ipc unittests for iOS since they largely require
multiprocess support.
- Separate the one file content/test needs out into a separate library

Bug: 1411704
Change-Id: I7edb42c18d1ad0a39001f33fa58bf6664b991999
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4240998
Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1104324}

content/test/BUILD.gn

@@ -506,7 +506,7 @@ static_library("test_support") {
     "//device/base/synchronization",
     "//google_apis",
     "//gpu/ipc:gl_in_process_context",
-    "//ipc:test_support",
+    "//ipc:test_sink",
     "//media",
     "//media/capture",
     "//media/capture/mojom:image_capture",
@@ -1610,7 +1610,7 @@ test("content_browsertests") {
     "//gpu",
     "//gpu/ipc/host",
     "//ipc",
-    "//ipc:test_support",
+    "//ipc:test_sink",
     "//media:media_buildflags",
     "//media:test_support",
     "//media/webrtc",
@@ -2777,7 +2777,7 @@ test("content_unittests") {
     "//gpu/ipc/common:test_support",
     "//gpu/ipc/host",
     "//gpu/ipc/service",
-    "//ipc:test_support",
+    "//ipc:test_sink",
     "//media:test_support",
     "//media/capture",
     "//media/midi:midi",

ipc/BUILD.gn

@@ -243,7 +243,23 @@ source_set("protobuf_support") {
   ]
 }
 
-if (use_blink) {
+static_library("test_sink") {
+  testonly = true
+  sources = [
+    "ipc_security_test_util.cc",
+    "ipc_security_test_util.h",
+    "ipc_test_sink.cc",
+    "ipc_test_sink.h",
+  ]
+  public_deps = [ ":ipc" ]
+  deps = [
+    "//base",
+    "//base/test:test_support",
+    "//mojo/core/test:test_support",
+  ]
+}
+
+if (!is_ios) {
   source_set("run_all_unittests") {
     testonly = true
 
@@ -336,16 +352,15 @@ if (use_blink) {
   static_library("test_support") {
     testonly = true
     sources = [
-      "ipc_security_test_util.cc",
-      "ipc_security_test_util.h",
       "ipc_test_base.cc",
       "ipc_test_base.h",
       "ipc_test_channel_listener.cc",
       "ipc_test_channel_listener.h",
-      "ipc_test_sink.cc",
-      "ipc_test_sink.h",
     ]
-    public_deps = [ ":ipc" ]
+    public_deps = [
+      ":ipc",
+      ":test_sink",
+    ]
     deps = [
       "//base",
       "//base/test:test_support",