Delay deferring resource requests until after first checking cache and extensions

content/browser/loader/resource_scheduler.cc

Index: content/browser/loader/resource_scheduler.cc
diff --git a/content/browser/loader/resource_scheduler.cc b/content/browser/loader/resource_scheduler.cc
index cda8a6c787bf5e679b9242456898468373ac750f..663281848c3ea4a9c408c15da3418c4e6a39f565 100644
--- a/content/browser/loader/resource_scheduler.cc
+++ b/content/browser/loader/resource_scheduler.cc
@@ -16,6 +16,7 @@
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
 #include "base/supports_user_data.h"
 #include "content/common/resource_messages.h"
 #include "content/public/browser/resource_controller.h"
@@ -51,6 +52,13 @@ const RequestAttributes kAttributeInFlight = 0x01;
 const RequestAttributes kAttributeDelayable = 0x02;
 const RequestAttributes kAttributeLayoutBlocking = 0x04;
 
+bool InDeferAfterCacheExperiment() {
+  std::string experiment =
+      base::FieldTrialList::FindFullName("ResourceSchedulerDeferAfterCache");
+  return base::StartsWith(experiment, "ExperimentYes",
+                          base::CompareCase::INSENSITIVE_ASCII);
+}
+
 }  // namespace
 
 static const size_t kDefaultMaxNumDelayableRequestsPerClient = 10;
@@ -242,9 +250,21 @@ class ResourceScheduler::ScheduledResourceRequest : public ResourceThrottle {
 
   // ResourceThrottle interface:
   void WillStartRequest(bool* defer) override {
+    if (InDeferAfterCacheExperiment()) {
+      *defer = false;
+      return;
+    }
     deferred_ = *defer = !ready_;
   }
 
+  void WillStartUsingNetwork(bool* defer) override {
+    if (InDeferAfterCacheExperiment()) {
+      deferred_ = *defer = !ready_;
+      return;
+    }
+    *defer = false;
+  }
+
   const char* GetNameForLogging() const override { return "ResourceScheduler"; }
 
   const ClientId client_id_;