Add Observer to TabAndroid

Bug: 1138729
Change-Id: I5c9b3cbf04e5bfebcc71d4ef1248da179f0ef8ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2481058
Commit-Queue: Gang Wu <gangwu@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818967}

chrome/browser/android/tab_android.cc

@@ -231,6 +231,14 @@ bool TabAndroid::IsHidden() {
   return Java_TabImpl_isHidden(env, weak_java_tab_.get(env));
 }
 
+void TabAndroid::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void TabAndroid::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
 void TabAndroid::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   delete this;
 }
@@ -274,6 +282,9 @@ void TabAndroid::InitWebContents(
 
   // Shows a warning notification for dangerous flags in about:flags.
   chrome::ShowBadFlagsPrompt(web_contents());
+
+  for (Observer& observer : observers_)
+    observer.OnInitWebContents(this);
 }
 
 void TabAndroid::UpdateDelegates(

chrome/browser/android/tab_android.h

@@ -14,6 +14,7 @@
 #include "base/android/scoped_java_ref.h"
 #include "base/callback_forward.h"
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "base/strings/string16.h"
 #include "base/supports_user_data.h"
 #include "chrome/browser/sync/glue/synced_tab_delegate_android.h"
@@ -49,6 +50,12 @@ class TabAndroid : public base::SupportsUserData {
     FULL_PRERENDERED_PAGE_LOAD = 3,
   };
 
+  class Observer : public base::CheckedObserver {
+   public:
+    // Called when WebContents is initialized.
+    virtual void OnInitWebContents(TabAndroid* tab) = 0;
+  };
+
   // Convenience method to retrieve the Tab associated with the passed
   // WebContents.  Can return NULL.
   static TabAndroid* FromWebContents(const content::WebContents* web_contents);
@@ -107,6 +114,12 @@ class TabAndroid : public base::SupportsUserData {
   bool IsCustomTab();
   bool IsHidden();
 
+  // Observers -----------------------------------------------------------------
+
+  // Adds/Removes an Observer.
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
   // Methods called from Java via JNI -----------------------------------------
 
   void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
@@ -179,6 +192,8 @@ class TabAndroid : public base::SupportsUserData {
   scoped_refptr<content::DevToolsAgentHost> devtools_host_;
   std::unique_ptr<browser_sync::SyncedTabDelegateAndroid> synced_tab_delegate_;
 
+  base::ObserverList<Observer> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(TabAndroid);
 };
 

chrome/browser/autocomplete/chrome_autocomplete_provider_client.cc

@@ -72,9 +72,12 @@ namespace {
 
 #if defined(OS_ANDROID)
 class AutocompleteClientTabAndroidUserData
-    : public TabAndroidUserData<AutocompleteClientTabAndroidUserData> {
+    : public TabAndroidUserData<AutocompleteClientTabAndroidUserData>,
+      public TabAndroid::Observer {
  public:
-  ~AutocompleteClientTabAndroidUserData() override = default;
+  ~AutocompleteClientTabAndroidUserData() override {
+    tab_->RemoveObserver(this);
+  }
 
   const GURL& GetStrippedURL() { return stripped_url_; }
 
@@ -89,10 +92,19 @@ class AutocompleteClientTabAndroidUserData
     }
   }
 
+  // TabAndroid::Observer implementation
+  void OnInitWebContents(TabAndroid* tab) override {
+    tab->RemoveUserData(UserDataKey());
+  }
+
  private:
-  explicit AutocompleteClientTabAndroidUserData(TabAndroid* tab) {}
+  explicit AutocompleteClientTabAndroidUserData(TabAndroid* tab) : tab_(tab) {
+    DCHECK(tab);
+    tab->AddObserver(this);
+  }
   friend class TabAndroidUserData<AutocompleteClientTabAndroidUserData>;
 
+  TabAndroid* tab_;
   bool initialized_ = false;
   GURL stripped_url_;
 
@@ -505,8 +517,6 @@ TabAndroid* ChromeAutocompleteProviderClient::GetTabOpenWithURL(
       } else {
         // Browser did not load the tab yet after Chrome started. To avoid
         // reloading WebContents, we just compare URLs.
-        // TODO(crbug.com/1138729): Delete user data after WebContents is
-        // initialized.
         AutocompleteClientTabAndroidUserData::CreateForTabAndroid(tab);
         AutocompleteClientTabAndroidUserData* user_data =
             AutocompleteClientTabAndroidUserData::FromTabAndroid(tab);