DoomPartialEntry should not attempt to doom an already doomed entry.

net/http/mock_http_cache.h

Index: net/http/mock_http_cache.h
diff --git a/net/http/mock_http_cache.h b/net/http/mock_http_cache.h
index d568c64db9a5d206a04973c2b82d37d289f97f30..bc7847b7bfff8b541ada5049b7a6c2453141b661 100644
--- a/net/http/mock_http_cache.h
+++ b/net/http/mock_http_cache.h
@@ -27,6 +27,12 @@ namespace net {
 class MockDiskEntry : public disk_cache::Entry,
                       public base::RefCounted<MockDiskEntry> {
  public:
+  enum DeferOp {
+    DEFER_NONE,
+    DEFER_CREATE,
+    DEFER_READ,
+  };
+
   explicit MockDiskEntry(const std::string& key);
 
   bool is_doomed() const { return doomed_; }
@@ -74,6 +80,14 @@ class MockDiskEntry : public disk_cache::Entry,
   // again or all subsequent tests will fail.
   static void IgnoreCallbacks(bool value);
 
+  // Defers invoking the callback for the given operation. Calling code should
+  // invoke ResumeDiskEntryOperation to resume.
+  void SetDefer(DeferOp defer_op) { defer_op_ = defer_op; }
+
+  // Resumes deferred cache operation by posting |resume_callback_| with
+  // |resume_return_code_|.
+  void ResumeDiskEntryOperation();
+
  private:
   friend class base::RefCounted<MockDiskEntry>;
   struct CallbackInfo;
@@ -106,6 +120,12 @@ class MockDiskEntry : public disk_cache::Entry,
   bool busy_;
   bool delayed_;
   bool cancel_;
+
+  // Used for pause and restart.
+  DeferOp defer_op_;
+  CompletionCallback resume_callback_;
+  int resume_return_code_;
+
   static bool ignore_callbacks_;
 };
 
@@ -161,8 +181,20 @@ class MockDiskCache : public disk_cache::Backend {
 
   void ReleaseAll();
 
+  // Returns true if a doomed entry exists with this key.
   bool IsDiskEntryDoomed(const std::string& key);
 
+  // Defers invoking the callback for the given operation. Calling code should
+  // invoke ResumeCacheOperation to resume.
+  void SetDefer(MockDiskEntry::DeferOp defer_op) { defer_op_ = defer_op; }
+
+  // Resume deferred cache operation by posting |resume_callback_| with
+  // |resume_return_code_|.
+  void ResumeCacheOperation();
+
+  // Returns a reference to the disk entry with the given |key|.
+  scoped_refptr<MockDiskEntry> GetDiskEntryRef(const std::string& key);
+
  private:
   using EntryMap = std::unordered_map<std::string, MockDiskEntry*>;
   class NotImplementedIterator;
@@ -177,6 +209,11 @@ class MockDiskCache : public disk_cache::Backend {
   bool soft_failures_;
   bool double_create_check_;
   bool fail_sparse_requests_;
+
+  // Used for pause and restart.
+  MockDiskEntry::DeferOp defer_op_;
+  CompletionCallback resume_callback_;
+  int resume_return_code_;
 };
 
 class MockBackendFactory : public HttpCache::BackendFactory {
@@ -244,7 +281,6 @@ class MockHttpCache {
   static void SetTestMode(int test_mode);
 
   // Functions to test the state of ActiveEntry.
-
   bool IsWriterPresent(const std::string& key);
   bool IsHeadersTransactionPresent(const std::string& key);
   int GetCountReaders(const std::string& key);