[IndexedDB] Adding transaction and value support to observers

third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp

Index: third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
diff --git a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
index 7efb5056a6ec0411888cf7f1faa27a85436c41f2..577a2247f30408d2e1461d12038ba07b53e88c95 100644
--- a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
+++ b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
@@ -41,12 +41,25 @@
 #include "modules/indexeddb/IDBOpenDBRequest.h"
 #include "modules/indexeddb/IDBTracing.h"
 #include "wtf/PtrUtil.h"
+
 #include <memory>
 
 using blink::WebIDBDatabase;
 
 namespace blink {
 
+IDBTransaction* IDBTransaction::createObserver(
+    ExecutionContext* executionContext,
+    int64_t id,
+    const HashSet<String>& scope,
+    IDBDatabase* db) {
+  DCHECK(!scope.isEmpty()) << "Observer transactions should operate on a "

[pwnall, 2017/01/10 01:41:11]

how about using "must" instead of "should" just like below?

[dmurph, 2017/01/10 20:40:08]

Done.

+                              "well-defined set of stores";
+  IDBTransaction* transaction =
+      new IDBTransaction(executionContext, id, scope, db);
+  return transaction;
+}
+
 IDBTransaction* IDBTransaction::createNonVersionChange(
     ScriptState* scriptState,
     int64_t id,
@@ -92,6 +105,24 @@ class DeactivateTransactionTask : public V8PerIsolateData::EndOfScopeTask {
 
 }  // namespace
 
+IDBTransaction::IDBTransaction(ExecutionContext* executionContext,
+                               int64_t id,
+                               const HashSet<String>& scope,
+                               IDBDatabase* db)
+    : ContextLifecycleObserver(executionContext),
+      m_id(id),
+      m_database(db),
+      m_mode(WebIDBTransactionModeReadOnly),
+      m_scope(scope),
+      m_state(Active) {
+  DCHECK(m_database);
+  DCHECK(!m_scope.isEmpty()) << "Observer transactions must operate "
+                                "on a well-defined set of stores";
+
+  DCHECK_EQ(m_state, Active);

[pwnall, 2017/01/10 01:41:11]

This seems a bit excessive, given that you're initializing the state right
above.

[dmurph, 2017/01/10 20:40:08]

Done.

+  m_database->transactionCreated(this);
+}
+
 IDBTransaction::IDBTransaction(ScriptState* scriptState,
                                int64_t id,
                                const HashSet<String>& scope,