Move IPC fuzzer switches and helpers from chrome/common to content/common.

content/public/common/BUILD.gn

Index: content/public/common/BUILD.gn
diff --git a/content/public/common/BUILD.gn b/content/public/common/BUILD.gn
index a3c06bcadd714a55d1b0bf3bfc7aad15746af8d8..59480bea81e6511c1230d1e04fbc1aae137eb2f9 100644
--- a/content/public/common/BUILD.gn
+++ b/content/public/common/BUILD.gn
@@ -8,6 +8,7 @@ import("//build/config/features.gni")
 import("//content/common/common.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//third_party/webrtc/build/webrtc.gni")
+import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
 
 # See //content/BUILD.gn for how this works.
 group("common") {
@@ -136,6 +137,14 @@ source_set("common_sources") {
       "webrtc_ip_handling_policy.h",
     ]
   }
+
+  if (enable_ipc_fuzzer) {
+    configs += [ "//tools/ipc_fuzzer:ipc_fuzzer_config" ]
+    sources += [
+      "external_ipc_dumper.cc",
+      "external_ipc_dumper.h",
+    ]
+  }
 }
 
 buildflag_header("features") {