AppCache: Move kUnknownResponseDataSize into a class.

AppCache's net::DiskCache wrapper header currently declares a static
const kUnknownResponseDataSize in the content namespace, resulting in a
copy in each translation unit that includes the header. While the copies
are most likely eliminated by the linker due to lack of use, this
declaration still pollutes the namespace.

This CL moves the constant into the HttpResponseInfoIOBuffer class, so
it is only emitted once.

This CL doesn't introduce any functional change.

Bug: 1055133
Change-Id: Ib9c8a339e6a543a908ee4c952bb0bc1174fa7dab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2069842
Commit-Queue: Victor Costan <pwnall@chromium.org>
Auto-Submit: Victor Costan <pwnall@chromium.org>
Reviewed-by: Joshua Bell <jsbell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744027}

content/browser/appcache/appcache_disk_cache_ops.cc

@@ -46,13 +46,16 @@ class WrappedPickleIOBuffer : public net::WrappedIOBuffer {
 
 // HttpResponseInfoIOBuffer ------------------------------------------
 
+// static
+constexpr int HttpResponseInfoIOBuffer::kUnknownResponseDataSize;
+
 HttpResponseInfoIOBuffer::HttpResponseInfoIOBuffer()
-    : response_data_size(kUnknownResponseDataSize) {}
+    : response_data_size(HttpResponseInfoIOBuffer::kUnknownResponseDataSize) {}
 
 HttpResponseInfoIOBuffer::HttpResponseInfoIOBuffer(
     std::unique_ptr<net::HttpResponseInfo> info)
     : http_info(std::move(info)),
-      response_data_size(kUnknownResponseDataSize) {}
+      response_data_size(HttpResponseInfoIOBuffer::kUnknownResponseDataSize) {}
 
 HttpResponseInfoIOBuffer::~HttpResponseInfoIOBuffer() = default;
 

content/browser/appcache/appcache_disk_cache_ops.h

@@ -22,12 +22,12 @@ namespace content {
 class AppCacheDiskCache;
 class AppCacheDiskCacheEntry;
 
-static const int kUnknownResponseDataSize = -1;
-
 // A refcounted wrapper for HttpResponseInfo so we can apply the
 // refcounting semantics used with IOBuffer with these structures too.
 struct CONTENT_EXPORT HttpResponseInfoIOBuffer
     : public base::RefCountedThreadSafe<HttpResponseInfoIOBuffer> {
+  static constexpr int kUnknownResponseDataSize = -1;
+
   std::unique_ptr<net::HttpResponseInfo> http_info;
   int response_data_size;
 

content/browser/appcache/appcache_storage_unittest.cc

@@ -68,7 +68,8 @@ TEST_F(AppCacheStorageTest, AddRemoveResponseInfo) {
   scoped_refptr<AppCacheResponseInfo> info =
       base::MakeRefCounted<AppCacheResponseInfo>(
           service.storage()->GetWeakPtr(), kManifestUrl, 111,
-          std::make_unique<net::HttpResponseInfo>(), kUnknownResponseDataSize);
+          std::make_unique<net::HttpResponseInfo>(),
+          HttpResponseInfoIOBuffer::kUnknownResponseDataSize);
 
   EXPECT_EQ(info.get(),
             service.storage()->working_set()->GetResponseInfo(111));
@@ -89,7 +90,8 @@ TEST_F(AppCacheStorageTest, ResponseInfoLifetime) {
     const GURL kManifestUrl("http://origin/");
     info = base::MakeRefCounted<AppCacheResponseInfo>(
         service.storage()->GetWeakPtr(), kManifestUrl, 111,
-        std::make_unique<net::HttpResponseInfo>(), kUnknownResponseDataSize);
+        std::make_unique<net::HttpResponseInfo>(),
+        HttpResponseInfoIOBuffer::kUnknownResponseDataSize);
 
     EXPECT_EQ(info.get(),
               service.storage()->working_set()->GetResponseInfo(111));