Implement THROTTLED priority semantics.

net/http/http_network_transaction_unittest.cc

Index: net/http/http_network_transaction_unittest.cc
diff --git a/net/http/http_network_transaction_unittest.cc b/net/http/http_network_transaction_unittest.cc
index daec89d43ff8a37caf250ffcb71cb68f0713b6fc..4853e901c71526142d0c832ae6d9c7e4960b77b2 100644
--- a/net/http/http_network_transaction_unittest.cc
+++ b/net/http/http_network_transaction_unittest.cc
@@ -135,7 +135,7 @@ class TestNetworkStreamThrottler : public NetworkThrottleManager {
   void UnthrottleAllRequests() {
     std::set<TestThrottle*> outstanding_throttles_copy(outstanding_throttles_);
     for (auto& throttle : outstanding_throttles_copy) {
-      if (throttle->IsThrottled())
+      if (throttle->IsBlocked())
         throttle->Unthrottle();
     }
   }
@@ -162,7 +162,11 @@ class TestNetworkStreamThrottler : public NetworkThrottleManager {
     ~TestThrottle() override { throttler_->OnThrottleDestroyed(this); }
 
     // Throttle
-    bool IsThrottled() const override { return throttled_; }
+    bool IsBlocked() const override { return throttled_; }
+    RequestPriority Priority() const override {
+      NOTREACHED();
+      return IDLE;
+    }
     void SetPriority(RequestPriority priority) override {
       throttler_->SetPriorityCalled(priority);
     }
@@ -176,7 +180,7 @@ class TestNetworkStreamThrottler : public NetworkThrottleManager {
       EXPECT_TRUE(throttled_);
 
       throttled_ = false;
-      delegate_->OnThrottleStateChanged();
+      delegate_->OnThrottleUnblocked(this);
     }
 
     bool throttled_;