WebSQL: Remove OriginInfo::DBInfo.

DBInfo now holds a single member, the database size. This CL replaces
the OriginInfo::databases_info map holding DBInfo values with a
`database_sizes` map.

Change-Id: I62e1e56fec26a9d964190d918ccf917c42f1ddfc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2634864
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Joshua Bell <jsbell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845083}

storage/browser/database/database_quota_client_unittest.cc

@@ -11,6 +11,7 @@
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/containers/contains.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/memory/scoped_refptr.h"
@@ -107,8 +108,8 @@ class MockDatabaseTracker : public DatabaseTracker {
     }
 
     void AddMockDatabase(const base::string16& name, int size) {
-      EXPECT_TRUE(database_info_.find(name) == database_info_.end());
-      database_info_[name].size = size;
+      EXPECT_FALSE(base::Contains(database_sizes_, name));
+      database_sizes_[name] = size;
       total_size_ += size;
     }
   };

storage/browser/database/database_tracker.cc

@@ -56,14 +56,14 @@ OriginInfo::~OriginInfo() = default;
 
 void OriginInfo::GetAllDatabaseNames(
     std::vector<base::string16>* databases) const {
-  for (const auto& pair : database_info_)
-    databases->push_back(pair.first);
+  for (const auto& name_and_size : database_sizes_)
+    databases->push_back(name_and_size.first);
 }
 
 int64_t OriginInfo::GetDatabaseSize(const base::string16& database_name) const {
-  auto it = database_info_.find(database_name);
-  if (it != database_info_.end())
-    return it->second.size;
+  auto it = database_sizes_.find(database_name);
+  if (it != database_sizes_.end())
+    return it->second;
   return 0;
 }
 

storage/browser/database/database_tracker.h

@@ -59,15 +59,12 @@ class COMPONENT_EXPORT(STORAGE_BROWSER) OriginInfo {
   int64_t GetDatabaseSize(const base::string16& database_name) const;
 
  protected:
-  struct DBInfo {
-    int64_t size;
-  };
   OriginInfo(const std::string& origin_identifier, int64_t total_size);
 
   std::string origin_identifier_;
   int64_t total_size_;
   base::Time last_modified_;
-  std::map<base::string16, DBInfo> database_info_;
+  std::map<base::string16, int64_t> database_sizes_;
 };
 
 // This class manages the main database and keeps track of open databases.
@@ -194,10 +191,14 @@ class COMPONENT_EXPORT(STORAGE_BROWSER) DatabaseTracker
     }
     void SetDatabaseSize(const base::string16& database_name,
                          int64_t new_size) {
-      int64_t old_size = 0;
-      if (database_info_.find(database_name) != database_info_.end())
-        old_size = database_info_[database_name].size;
-      database_info_[database_name].size = new_size;
+      // If the name does not exist in the map, operator[] creates a new entry
+      // with a default-constructed value. The default-constructed value for
+      // int64_t is zero (0), which is exactly what we want `old_size` to be set
+      // to in this case.
+      int64_t& database_size = database_sizes_[database_name];
+      int64_t old_size = database_size;
+
+      database_size = new_size;
       if (new_size != old_size)
         total_size_ += new_size - old_size;
     }