[DevTools] Create last agents on attach, modify InspectorDatabaseAgent to support it.

third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h

Index: third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h
diff --git a/third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h b/third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h
index 9b6059eede6a8d8f4f4cd51cbe28d22c36f63d2d..b911b6c33cf96f883d90cf1a7e21bc5fdf8c9eb9 100644
--- a/third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h
+++ b/third_party/WebKit/Source/modules/webdatabase/DatabaseTracker.h
@@ -42,6 +42,7 @@ namespace blink {
 
 class Database;
 class DatabaseContext;
+class InspectorDatabaseAgent;
 class SecurityOrigin;
 
 class MODULES_EXPORT DatabaseTracker {
@@ -64,6 +65,7 @@ public:
     unsigned long long getMaxSizeForDatabase(const Database*);
 
     void closeDatabasesImmediately(SecurityOrigin*, const String& name);
+    void registerAllDatabasesInInspector(InspectorDatabaseAgent*);

[michaeln, 2016/04/13 22:18:18]

It'd be nice to not have a dependency on the inspector here.

We could do this more generically with a function that returns a set of all open
Databases. I guess it'd need to be a GarbageCollectedFinalized set of some kind
which traced each database in the set as a Member<>?

Or maybe a forEachOpenDatabase(...) that takes a callback of some kind.

[dgozman, 2016/04/13 22:26:04]

I'd rather go for callback than Memeber<> collection to avoid all extra wrapping
and ownerhsip thoughts. I can't judge whether this particular class should not
depend on inspector, since there are a bunch of quite similarly named classes in
the same directory - it's hard to choose correct dependencies.

On the side note, I was surprised that DatabaseManager does not have a registry
of all databases and I had to look into DatabaseTracker.

 
     void prepareToOpenDatabase(Database*);
     void failedToOpenDatabase(Database*);