Add UMA that periodically logs number of outstanding requests

content/browser/loader/DEPS

 # The core loading code in this directory is being transitioned into a separate
 # Mojo networking service. See http://crbug.com/598073. The first stage is to
 # decouple the code that will be moved from the rest of content. These rules
 # help ensure that we don't add more includes, and can progressively reduce the
 # code's dependencies.
 #
 # For each file, the first section shows includes that are allowed (i.e. because
 # they are for files that will be moving as well). The second section, separated
 # by a comment, lists files that we will have to decouple.
 specific_include_rules = {
@@ skipping 147 matching lines @@
     "+content/browser/service_worker/foreign_fetch_request_handler.h",
     "+content/browser/service_worker/link_header_support.h",
     "+content/browser/service_worker/service_worker_context_wrapper.h",
     "+content/browser/service_worker/service_worker_navigation_handle_core.h",
     "+content/browser/service_worker/service_worker_request_handler.h",
     "+content/browser/streams/stream.h",
     "+content/browser/streams/stream_context.h",
     "+content/browser/streams/stream_registry.h",
     "+content/common/content_export.h",
     "+content/common/net/url_request_service_worker_data.h",
+    "+content/common/site_isolation_policy.h",
     "+content/public/browser/browser_thread.h",
     "+content/public/browser/navigation_ui_data.h",
     "+content/public/browser/plugin_service.h",
     "+content/public/browser/resource_request_details.h",
     "+content/public/browser/stream_handle.h",
     "+content/public/browser/stream_info.h",
     "+content/public/common/browser_side_navigation_policy.h",
     "+content/public/common/content_features.h",
     "+content/public/common/content_switches.h",
     "+content/public/common/request_context_type.h",
@@ skipping 168 matching lines @@
     "+content/browser/loader/navigation_resource_throttle.h"
   ],
   "wake_lock_resource_throttle\.(cc|h)": [
     "-content",
     "+content/browser/loader/wake_lock_resource_throttle.h",
     "+content/browser/service_manager/service_manager_context.h",
     "+content/public/browser/browser_thread.h",
     "+content/public/browser/resource_throttle.h",
   ],
 }