Add an InterfaceInvalidator to ExecutionContexts

This allows the lifetime of WeakInterfacePtrs to be tied to an
ExecutionContext, as now the interface can be tied to an invalidator whose
lifetime is bound to an ExecutionContext.

Bug: 800641
Change-Id: I0c922c90a89108f56c179b74170a8e0e2a5f666f
Reviewed-on: https://chromium-review.googlesource.com/872470
Commit-Queue: Austin Tankiang <austinct@google.com>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532310}

third_party/WebKit/Source/core/dom/DocumentTest.cpp

@@ -945,6 +945,27 @@ TEST_F(DocumentTest, ViewportPropagationNoRecalc) {
   EXPECT_EQ(1, new_element_count - old_element_count);
 }
 
+class InvalidatorObserver : public InterfaceInvalidator::Observer {
+ public:
+  void OnInvalidate() { ++invalidate_called_counter_; }
+
+  int CountInvalidateCalled() const { return invalidate_called_counter_; }
+
+ private:
+  int invalidate_called_counter_ = 0;
+};
+
+TEST_F(DocumentTest, InterfaceInvalidatorDestruction) {
+  InvalidatorObserver obs;
+  InterfaceInvalidator* invalidator = GetDocument().GetInterfaceInvalidator();
+  invalidator->AddObserver(&obs);
+  EXPECT_EQ(obs.CountInvalidateCalled(), 0);
+
+  GetDocument().Shutdown();
+  EXPECT_FALSE(GetDocument().GetInterfaceInvalidator());
+  EXPECT_EQ(1, obs.CountInvalidateCalled());
+}
+
 typedef bool TestParamRootLayerScrolling;
 class ParameterizedDocumentTest
     : public ::testing::WithParamInterface<TestParamRootLayerScrolling>,

third_party/WebKit/Source/core/dom/ExecutionContext.cpp

@@ -51,7 +51,8 @@ ExecutionContext::ExecutionContext()
       is_context_paused_(false),
       is_context_destroyed_(false),
       window_interaction_tokens_(0),
-      referrer_policy_(kReferrerPolicyDefault) {}
+      referrer_policy_(kReferrerPolicyDefault),
+      invalidator_(std::make_unique<InterfaceInvalidator>()) {}
 
 ExecutionContext::~ExecutionContext() = default;
 
@@ -87,6 +88,7 @@ void ExecutionContext::UnpausePausableObjects() {
 
 void ExecutionContext::NotifyContextDestroyed() {
   is_context_destroyed_ = true;
+  invalidator_.reset();
   ContextLifecycleNotifier::NotifyContextDestroyed();
 }
 

third_party/WebKit/Source/core/dom/ExecutionContext.h

@@ -55,6 +55,7 @@ class DOMTimerCoordinator;
 class ErrorEvent;
 class EventQueue;
 class EventTarget;
+class InterfaceInvalidator;
 class LocalDOMWindow;
 class PausableObject;
 class PublicURLManager;
@@ -205,6 +206,8 @@ class CORE_EXPORT ExecutionContext : public ContextLifecycleNotifier,
 
   virtual scoped_refptr<WebTaskRunner> GetTaskRunner(TaskType) = 0;
 
+  InterfaceInvalidator* GetInterfaceInvalidator() { return invalidator_.get(); }
+
  protected:
   ExecutionContext();
   virtual ~ExecutionContext();
@@ -229,6 +232,9 @@ class CORE_EXPORT ExecutionContext : public ContextLifecycleNotifier,
   int window_interaction_tokens_;
 
   ReferrerPolicy referrer_policy_;
+
+  std::unique_ptr<InterfaceInvalidator> invalidator_;
+
   DISALLOW_COPY_AND_ASSIGN(ExecutionContext);
 };