Oilpan: Prepare to move AbstractSQLStatementBackend and SQLStatementBackend to Oilpan heap.

They are ThreadSafeRefCounted because an object is created in a context thread,
is enqueued into a SQLTransactionBackend, the SQLTransactionBackend is moved to
a database thread, then the database thread takes a SQLStatementBackend in the
queue.
We don't need to care about it in Oilpan. SQLTransactionBackend is correctly
transferred with CrossThreadPersistent.

BUG=347902

Review URL: https://codereview.chromium.org/205823002

git-svn-id: svn://svn.chromium.org/blink/trunk@169622 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -26,15 +26,17 @@
 #ifndef AbstractSQLStatementBackend_h
 #define AbstractSQLStatementBackend_h
 
+#include "heap/Handle.h"
 #include "modules/webdatabase/SQLError.h"
 #include "modules/webdatabase/SQLResultSet.h"
 #include "wtf/ThreadSafeRefCounted.h"
 
 namespace WebCore {
 
-class AbstractSQLStatementBackend : public ThreadSafeRefCounted<AbstractSQLStatementBackend> {
+class AbstractSQLStatementBackend : public ThreadSafeRefCountedWillBeGarbageCollectedFinalized<AbstractSQLStatementBackend> {
 public:
     virtual ~AbstractSQLStatementBackend() { }
+    virtual void trace(Visitor*) = 0;
 
     virtual PassRefPtr<SQLError> sqlError() const = 0;
     virtual PassRefPtr<SQLResultSet> sqlResultSet() const = 0;

third_party/WebKit/Source/modules/webdatabase/SQLStatementBackend.cpp

@@ -71,10 +71,10 @@
 
 namespace WebCore {
 
-PassRefPtr<SQLStatementBackend> SQLStatementBackend::create(PassOwnPtr<AbstractSQLStatement> frontend,
+PassRefPtrWillBeRawPtr<SQLStatementBackend> SQLStatementBackend::create(PassOwnPtr<AbstractSQLStatement> frontend,
     const String& statement, const Vector<SQLValue>& arguments, int permissions)
 {
-    return adoptRef(new SQLStatementBackend(frontend, statement, arguments, permissions));
+    return adoptRefWillBeNoop(new SQLStatementBackend(frontend, statement, arguments, permissions));
 }
 
 SQLStatementBackend::SQLStatementBackend(PassOwnPtr<AbstractSQLStatement> frontend,
@@ -89,6 +89,10 @@ SQLStatementBackend::SQLStatementBackend(PassOwnPtr<AbstractSQLStatement> fronte
     m_frontend->setBackend(this);
 }
 
+void SQLStatementBackend::trace(Visitor*)
+{
+}
+
 AbstractSQLStatement* SQLStatementBackend::frontend()
 {
     return m_frontend.get();

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

@@ -44,8 +44,9 @@ class SQLTransactionBackend;
 
 class SQLStatementBackend FINAL : public AbstractSQLStatementBackend {
 public:
-    static PassRefPtr<SQLStatementBackend> create(PassOwnPtr<AbstractSQLStatement>,
+    static PassRefPtrWillBeRawPtr<SQLStatementBackend> create(PassOwnPtr<AbstractSQLStatement>,
         const String& sqlStatement, const Vector<SQLValue>& arguments, int permissions);
+    virtual void trace(Visitor*) OVERRIDE;
 
     bool execute(DatabaseBackend*);
     bool lastExecutionFailedDueToQuota() const;

third_party/WebKit/Source/modules/webdatabase/SQLTransactionBackend.cpp

@@ -373,7 +373,9 @@ SQLTransactionBackend::~SQLTransactionBackend()
 void SQLTransactionBackend::trace(Visitor* visitor)
 {
     visitor->trace(m_frontend);
+    visitor->trace(m_currentStatementBackend);
     visitor->trace(m_database);
+    visitor->trace(m_statementQueue);
 }
 
 void SQLTransactionBackend::doCleanup()
@@ -466,7 +468,7 @@ SQLTransactionBackend::StateFunction SQLTransactionBackend::stateFunctionFor(SQL
     return stateFunctions[static_cast<int>(state)];
 }
 
-void SQLTransactionBackend::enqueueStatementBackend(PassRefPtr<SQLStatementBackend> statementBackend)
+void SQLTransactionBackend::enqueueStatementBackend(PassRefPtrWillBeRawPtr<SQLStatementBackend> statementBackend)
 {
     MutexLocker locker(m_statementMutex);
     m_statementQueue.append(statementBackend);
@@ -521,9 +523,7 @@ void SQLTransactionBackend::performNextStep()
 void SQLTransactionBackend::executeSQL(PassOwnPtr<AbstractSQLStatement> statement,
     const String& sqlStatement, const Vector<SQLValue>& arguments, int permissions)
 {
-    RefPtr<SQLStatementBackend> statementBackend;
-    statementBackend = SQLStatementBackend::create(statement, sqlStatement, arguments, permissions);
-    enqueueStatementBackend(statementBackend);
+    enqueueStatementBackend(SQLStatementBackend::create(statement, sqlStatement, arguments, permissions));
 }
 
 void SQLTransactionBackend::notifyDatabaseThreadIsShuttingDown()

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

@@ -86,7 +86,7 @@ private:
 
     void doCleanup();
 
-    void enqueueStatementBackend(PassRefPtr<SQLStatementBackend>);
+    void enqueueStatementBackend(PassRefPtrWillBeRawPtr<SQLStatementBackend>);
 
     // State Machine functions:
     virtual StateFunction stateFunctionFor(SQLTransactionState) OVERRIDE;
@@ -110,7 +110,7 @@ private:
     void getNextStatement();
 
     RefPtrWillBeMember<AbstractSQLTransaction> m_frontend; // Has a reference cycle, and will break in doCleanup().
-    RefPtr<SQLStatementBackend> m_currentStatementBackend;
+    RefPtrWillBeMember<SQLStatementBackend> m_currentStatementBackend;
 
     RefPtrWillBeMember<DatabaseBackend> m_database;
     RefPtr<SQLTransactionWrapper> m_wrapper;
@@ -126,7 +126,7 @@ private:
     bool m_hasVersionMismatch;
 
     Mutex m_statementMutex;
-    Deque<RefPtr<SQLStatementBackend> > m_statementQueue;
+    Deque<RefPtrWillBeMember<SQLStatementBackend> > m_statementQueue;
 
     OwnPtr<SQLiteTransaction> m_sqliteTransaction;
 };