Use ObserverList for TranslateInfobarDelegate

TranslateInfobarDelegate is currently only allows for one
observer. This change replaces its observer_ property
with a ObserverList so that more than one object can
be an observer.

Change-Id: I67c2a1ee2e2bee8ba532bc4b4adc1d2237dc1bd8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2153330Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760567}

chrome/browser/ui/android/infobars/translate_compact_infobar.cc

@@ -39,7 +39,7 @@ std::unique_ptr<infobars::InfoBar> ChromeTranslateClient::CreateInfoBar(
 TranslateCompactInfoBar::TranslateCompactInfoBar(
     std::unique_ptr<translate::TranslateInfoBarDelegate> delegate)
     : InfoBarAndroid(std::move(delegate)), action_flags_(FLAG_NONE) {
-  GetDelegate()->SetObserver(this);
+  GetDelegate()->AddObserver(this);
 
   // Flip the translate bit if auto translate is enabled.
   if (GetDelegate()->translate_step() == translate::TRANSLATE_STEP_TRANSLATING)
@@ -47,7 +47,7 @@ TranslateCompactInfoBar::TranslateCompactInfoBar(
 }
 
 TranslateCompactInfoBar::~TranslateCompactInfoBar() {
-  GetDelegate()->SetObserver(nullptr);
+  GetDelegate()->RemoveObserver(this);
 }
 
 ScopedJavaLocalRef<jobject> TranslateCompactInfoBar::CreateRenderInfoBar(
@@ -225,5 +225,5 @@ bool TranslateCompactInfoBar::IsDeclinedByUser() {
 void TranslateCompactInfoBar::OnTranslateInfoBarDelegateDestroyed(
     translate::TranslateInfoBarDelegate* delegate) {
   DCHECK_EQ(GetDelegate(), delegate);
-  GetDelegate()->SetObserver(nullptr);
+  GetDelegate()->RemoveObserver(this);
 }

components/translate/core/browser/mock_translate_infobar_delegate.h

@@ -49,7 +49,8 @@ class MockTranslateInfoBarDelegate
   MOCK_CONST_METHOD1(language_name_at, base::string16(size_t index));
   MOCK_CONST_METHOD0(original_language_name, base::string16());
   MOCK_CONST_METHOD0(ShouldAlwaysTranslate, bool());
-  MOCK_METHOD1(SetObserver, void(Observer* observer));
+  MOCK_METHOD1(AddObserver, void(Observer* observer));
+  MOCK_METHOD1(RemoveObserver, void(Observer* observer));
 };
 
 class MockTranslateInfoBarDelegateFactory {

components/translate/core/browser/translate_infobar_delegate.cc

@@ -52,8 +52,9 @@ const base::Feature kTranslateCompactUI{"TranslateCompactUI",
 const size_t TranslateInfoBarDelegate::kNoIndex = TranslateUIDelegate::kNoIndex;
 
 TranslateInfoBarDelegate::~TranslateInfoBarDelegate() {
-  if (observer_)
-    observer_->OnTranslateInfoBarDelegateDestroyed(this);
+  for (auto& observer : observers_) {
+    observer.OnTranslateInfoBarDelegateDestroyed(this);
+  }
 }
 
 infobars::InfoBarDelegate::InfoBarIdentifier
@@ -111,8 +112,10 @@ void TranslateInfoBarDelegate::Create(
   }
 
   // Try to reuse existing translate infobar delegate.
-  if (old_delegate && old_delegate->observer_) {
-    old_delegate->observer_->OnTranslateStepChanged(step, error_type);
+  if (old_delegate) {
+    for (auto& observer : old_delegate->observers_) {
+      observer.OnTranslateStepChanged(step, error_type);
+    }
     return;
   }
 
@@ -140,10 +143,6 @@ base::string16 TranslateInfoBarDelegate::language_name_at(size_t index) const {
   return ui_delegate_.GetLanguageNameAt(index);
 }
 
-void TranslateInfoBarDelegate::SetObserver(Observer* observer) {
-  observer_ = observer;
-}
-
 base::string16 TranslateInfoBarDelegate::original_language_name() const {
   return language_name_at(ui_delegate_.GetOriginalLanguageIndex());
 }
@@ -435,6 +434,14 @@ TranslateDriver* TranslateInfoBarDelegate::GetTranslateDriver() {
   return translate_manager_->translate_client()->GetTranslateDriver();
 }
 
+void TranslateInfoBarDelegate::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void TranslateInfoBarDelegate::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
 TranslateInfoBarDelegate::TranslateInfoBarDelegate(
     const base::WeakPtr<TranslateManager>& translate_manager,
     bool is_off_the_record,
@@ -450,8 +457,7 @@ TranslateInfoBarDelegate::TranslateInfoBarDelegate(
       translate_manager_(translate_manager),
       error_type_(error_type),
       prefs_(translate_manager->translate_client()->GetTranslatePrefs()),
-      triggered_from_menu_(triggered_from_menu),
-      observer_(nullptr) {
+      triggered_from_menu_(triggered_from_menu) {
   DCHECK_NE((step_ == translate::TRANSLATE_STEP_TRANSLATE_ERROR),
             (error_type_ == TranslateErrors::NONE));
   DCHECK(translate_manager_);
@@ -462,9 +468,16 @@ int TranslateInfoBarDelegate::GetIconId() const {
 }
 
 void TranslateInfoBarDelegate::InfoBarDismissed() {
-  bool declined = observer_
-                      ? observer_->IsDeclinedByUser()
-                      : (step_ == translate::TRANSLATE_STEP_BEFORE_TRANSLATE);
+  bool declined = false;
+  bool has_observer = false;
+  for (auto& observer : observers_) {
+    has_observer = true;
+    if (observer.IsDeclinedByUser())
+      declined = true;
+  }
+
+  if (!has_observer)
+    declined = step_ == translate::TRANSLATE_STEP_BEFORE_TRANSLATE;
 
   if (declined) {
     // The user closed the infobar without clicking the translate button.

components/translate/core/browser/translate_infobar_delegate.h

@@ -16,6 +16,8 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "base/observer_list_types.h"
 #include "build/build_config.h"
 #include "components/infobars/core/infobar_delegate.h"
 #include "components/translate/core/browser/translate_prefs.h"
@@ -43,7 +45,7 @@ class TranslateManager;
 class TranslateInfoBarDelegate : public infobars::InfoBarDelegate {
  public:
   // An observer to handle different translate steps' UI changes.
-  class Observer {
+  class Observer : public base::CheckedObserver {
    public:
     // Handles UI changes on the translate step given.
     virtual void OnTranslateStepChanged(translate::TranslateStep step,
@@ -53,9 +55,6 @@ class TranslateInfoBarDelegate : public infobars::InfoBarDelegate {
     // Called when the TranslateInfoBarDelegate instance is destroyed.
     virtual void OnTranslateInfoBarDelegateDestroyed(
         TranslateInfoBarDelegate* delegate) = 0;
-
-   protected:
-    virtual ~Observer() {}
   };
 
   static const size_t kNoIndex;
@@ -216,8 +215,11 @@ class TranslateInfoBarDelegate : public infobars::InfoBarDelegate {
   // May return NULL if the driver has been destroyed.
   TranslateDriver* GetTranslateDriver();
 
-  // Set a observer.
-  virtual void SetObserver(Observer* observer);
+  // Add an observer.
+  virtual void AddObserver(Observer* observer);
+
+  // Remove an observer.
+  virtual void RemoveObserver(Observer* observer);
 
   // InfoBarDelegate:
   infobars::InfoBarDelegate::InfoBarIdentifier GetIdentifier() const override;
@@ -255,9 +257,9 @@ class TranslateInfoBarDelegate : public infobars::InfoBarDelegate {
   // (due to language detection, preferences...)
   bool triggered_from_menu_;
 
-  // A observer to handle front-end changes on different steps.
+  // Observers to handle front-end changes on different steps.
   // It's only used when we try to reuse the existing UI.
-  Observer* observer_;
+  base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateInfoBarDelegate);
 };

ios/chrome/browser/translate/translate_infobar_delegate_observer_bridge.mm

@@ -14,13 +14,13 @@ TranslateInfobarDelegateObserverBridge::TranslateInfobarDelegateObserverBridge(
     translate::TranslateInfoBarDelegate* translate_infobar_delegate,
     id<TranslateInfobarDelegateObserving> owner)
     : translate_infobar_delegate_(translate_infobar_delegate), owner_(owner) {
-  translate_infobar_delegate_->SetObserver(this);
+  translate_infobar_delegate_->AddObserver(this);
 }
 
 TranslateInfobarDelegateObserverBridge::
     ~TranslateInfobarDelegateObserverBridge() {
   if (translate_infobar_delegate_) {
-    translate_infobar_delegate_->SetObserver(nullptr);
+    translate_infobar_delegate_->RemoveObserver(this);
   }
 }
 
@@ -41,6 +41,6 @@ void TranslateInfobarDelegateObserverBridge::
     OnTranslateInfoBarDelegateDestroyed(
         translate::TranslateInfoBarDelegate* delegate) {
   DCHECK_EQ(translate_infobar_delegate_, delegate);
-  translate_infobar_delegate_->SetObserver(nullptr);
+  translate_infobar_delegate_->RemoveObserver(this);
   translate_infobar_delegate_ = nullptr;
 }

ios/chrome/browser/translate/translate_infobar_delegate_observer_bridge_unittest.mm

@@ -56,7 +56,7 @@ class TranslateInfobarDelegateObserverBridgeTest : public PlatformTest {
       : delegate_factory_("fr", "en"),
         observer_([[TestTranslateInfoBarDelegateObserver alloc] init]) {
     // Make sure the observer bridge sets up itself as an observer.
-    EXPECT_CALL(*GetDelegate(), SetObserver(_)).Times(1);
+    EXPECT_CALL(*GetDelegate(), AddObserver(_));
 
     observer_bridge_ = std::make_unique<TranslateInfobarDelegateObserverBridge>(
         delegate_factory_.GetMockTranslateInfoBarDelegate(), observer_);
@@ -64,7 +64,7 @@ class TranslateInfobarDelegateObserverBridgeTest : public PlatformTest {
 
   ~TranslateInfobarDelegateObserverBridgeTest() override {
     // Make sure the observer bridge removes itself as an observer.
-    EXPECT_CALL(*GetDelegate(), SetObserver(nullptr)).Times(1);
+    EXPECT_CALL(*GetDelegate(), RemoveObserver(_));
   }
 
   MockTranslateInfoBarDelegate* GetDelegate() {