Break up chrome/common:common

chrome/common/page_load_metrics/BUILD.gn

+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//mojo/public/tools/bindings/mojom.gni")
+
+mojom("page_load_metrics_mojom") {
+  sources = [
+    "page_load_metrics.mojom",
+  ]
+
+  public_deps = [
+    "//mojo/common:common_custom_types",
+  ]
+}
+
+source_set("page_load_metrics") {
+  sources = [
+    "page_load_metrics_constants.h",
+    "page_load_metrics_messages.h",
+    "page_load_metrics_param_traits.cc",
+    "page_load_metrics_param_traits.h",
+    "page_load_metrics_util.cc",
+    "page_load_metrics_util.h",
+    "page_load_timing.cc",
+    "page_load_timing.h",
+    "page_track_decider.cc",
+    "page_track_decider.h",
+  ]
+  deps = [
+    ":page_load_metrics_mojom",
+    "//base",
+    "//ipc",
+    "//net",
+    "//third_party/WebKit/public:blink_headers",
+    "//url",
+  ]
+}