AppCache: Clean up AppCacheDiskCache::PendingCall.

This CL has no functional changes.

The following cleanups were applied.

1) Made data members were const where applicable.
2) Added explicit {copy,move} {constructor,assignment} declarations.
3) Removed unnecessary default constructor.
4) Applied clang-tidy suggestion for push_back() -> emplace_back().

Change-Id: I5d3c55280f4a6020a743096cf603d90b135e875e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2464979
Auto-Submit: Victor Costan <pwnall@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817168}

content/browser/appcache/appcache_disk_cache.cc

@@ -252,8 +252,7 @@ net::Error AppCacheDiskCache::CreateEntry(
     return net::ERR_ABORTED;
 
   if (is_initializing_or_waiting_to_initialize()) {
-    pending_calls_.push_back(
-        PendingCall(CREATE, key, entry, std::move(callback)));
+    pending_calls_.emplace_back(CREATE, key, entry, std::move(callback));
     return net::ERR_IO_PENDING;
   }
 
@@ -273,8 +272,7 @@ net::Error AppCacheDiskCache::OpenEntry(int64_t key,
     return net::ERR_ABORTED;
 
   if (is_initializing_or_waiting_to_initialize()) {
-    pending_calls_.push_back(
-        PendingCall(OPEN, key, entry, std::move(callback)));
+    pending_calls_.emplace_back(OPEN, key, entry, std::move(callback));
     return net::ERR_IO_PENDING;
   }
 
@@ -292,8 +290,7 @@ net::Error AppCacheDiskCache::DoomEntry(int64_t key,
     return net::ERR_ABORTED;
 
   if (is_initializing_or_waiting_to_initialize()) {
-    pending_calls_.push_back(
-        PendingCall(DOOM, key, nullptr, std::move(callback)));
+    pending_calls_.emplace_back(DOOM, key, nullptr, std::move(callback));
     return net::ERR_IO_PENDING;
   }
 
@@ -313,9 +310,6 @@ AppCacheDiskCache::AppCacheDiskCache(bool use_simple_cache)
       is_disabled_(false),
       is_waiting_to_initialize_(false) {}
 
-AppCacheDiskCache::PendingCall::PendingCall()
-    : call_type(CREATE), key(0), entry(nullptr) {}
-
 AppCacheDiskCache::PendingCall::PendingCall(
     PendingCallType call_type,
     int64_t key,
@@ -326,7 +320,7 @@ AppCacheDiskCache::PendingCall::PendingCall(
       entry(entry),
       callback(std::move(callback)) {}
 
-AppCacheDiskCache::PendingCall::PendingCall(PendingCall&& other) = default;
+AppCacheDiskCache::PendingCall::PendingCall(PendingCall&&) = default;
 
 AppCacheDiskCache::PendingCall::~PendingCall() = default;
 

content/browser/appcache/appcache_disk_cache.h

@@ -112,18 +112,21 @@ class CONTENT_EXPORT AppCacheDiskCache {
     DOOM
   };
   struct PendingCall {
-    PendingCall();
     PendingCall(PendingCallType call_type,
                 int64_t key,
                 AppCacheDiskCacheEntry** entry,
                 net::CompletionOnceCallback callback);
-    PendingCall(PendingCall&& other);
+
+    PendingCall(const PendingCall&) = delete;
+    PendingCall& operator=(const PendingCall&) = delete;
+    PendingCall(PendingCall&&);
+    PendingCall& operator=(PendingCall&&) = delete;
 
     ~PendingCall();
 
-    PendingCallType call_type;
-    int64_t key;
-    AppCacheDiskCacheEntry** entry;
+    const PendingCallType call_type;
+    const int64_t key;
+    AppCacheDiskCacheEntry** const entry;
     net::CompletionOnceCallback callback;
   };