[ios][PhishGuard] Make cross-platform GetTaskRunner()

This CL adds utility functions that provide a cross-platform interface
for obtaining the task runner for the IO and UI threads.

Note that base::CreateSingleThreadTaskRunner() is an older approach
to obtaining the task runners for the IO and UI threads. But it is
still used in iOS.

Bug: 1147967
Change-Id: I2d16613864f5a5b927157b5a26377d7513032905
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2559793
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Reviewed-by: Ali Juma <ajuma@chromium.org>
Reviewed-by: Bettina Dea <bdea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833082}

components/safe_browsing/content/common/thread_utils.cc

@@ -4,6 +4,7 @@
 
 #include "components/safe_browsing/core/common/thread_utils.h"
 
+#include "base/notreached.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 
@@ -35,4 +36,16 @@ base::TaskTraits CreateTaskTraits(ThreadID thread_id) {
   return {BrowserThreadID(thread_id)};
 }
 
+scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner(ThreadID thread_id) {
+  switch (thread_id) {
+    case ThreadID::UI:
+      return content::GetUIThreadTaskRunner({});
+    case ThreadID::IO:
+      return content::GetIOThreadTaskRunner({});
+    default:
+      NOTREACHED();
+      return content::GetUIThreadTaskRunner({});
+  }
+}
+
 }  // namespace safe_browsing

components/safe_browsing/content/password_protection/password_protection_request.cc

@@ -18,7 +18,6 @@
 #include "components/safe_browsing/core/db/database_manager.h"
 #include "components/safe_browsing/core/features.h"
 #include "components/url_formatter/url_formatter.h"
-#include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/navigation_throttle.h"
 #include "net/base/escape.h"
 #include "net/base/load_flags.h"
@@ -171,7 +170,7 @@ void PasswordProtectionRequest::CheckWhitelist() {
   auto result_callback =
       base::BindOnce(&OnWhitelistCheckDoneOnIO, GetWeakPtr());
   tracker_.PostTask(
-      content::GetIOThreadTaskRunner({}).get(), FROM_HERE,
+      GetTaskRunner(ThreadID::IO).get(), FROM_HERE,
       base::BindOnce(&AllowlistCheckerClient::StartCheckCsdWhitelist,
                      password_protection_service_->database_manager(),
                      main_frame_url_, std::move(result_callback)));
@@ -182,10 +181,11 @@ void PasswordProtectionRequest::OnWhitelistCheckDoneOnIO(
     base::WeakPtr<PasswordProtectionRequest> weak_request,
     bool match_whitelist) {
   // Don't access weak_request on IO thread. Move it back to UI thread first.
-  content::GetUIThreadTaskRunner({})->PostTask(
-      FROM_HERE,
-      base::BindOnce(&PasswordProtectionRequest::OnWhitelistCheckDone,
-                     weak_request, match_whitelist));
+  GetTaskRunner(ThreadID::UI)
+      ->PostTask(
+          FROM_HERE,
+          base::BindOnce(&PasswordProtectionRequest::OnWhitelistCheckDone,
+                         weak_request, match_whitelist));
 }
 
 void PasswordProtectionRequest::OnWhitelistCheckDone(bool match_whitelist) {
@@ -350,11 +350,12 @@ void PasswordProtectionRequest::GetDomFeatures() {
       main_frame_url_,
       base::BindRepeating(&PasswordProtectionRequest::OnGetDomFeatures,
                           GetWeakPtr()));
-  content::GetUIThreadTaskRunner({})->PostDelayedTask(
-      FROM_HERE,
-      base::BindOnce(&PasswordProtectionRequest::OnGetDomFeatureTimeout,
-                     GetWeakPtr()),
-      base::TimeDelta::FromMilliseconds(kDomFeatureTimeoutMs));
+  GetTaskRunner(ThreadID::UI)
+      ->PostDelayedTask(
+          FROM_HERE,
+          base::BindOnce(&PasswordProtectionRequest::OnGetDomFeatureTimeout,
+                         GetWeakPtr()),
+          base::TimeDelta::FromMilliseconds(kDomFeatureTimeoutMs));
   dom_feature_start_time_ = base::TimeTicks::Now();
 }
 
@@ -540,10 +541,12 @@ void PasswordProtectionRequest::StartTimeout() {
   // The weak pointer used for the timeout will be invalidated (and
   // hence would prevent the timeout) if the check completes on time and
   // execution reaches Finish().
-  content::GetUIThreadTaskRunner({})->PostDelayedTask(
-      FROM_HERE,
-      base::BindOnce(&PasswordProtectionRequest::Cancel, GetWeakPtr(), true),
-      base::TimeDelta::FromMilliseconds(request_timeout_in_ms_));
+  GetTaskRunner(ThreadID::UI)
+      ->PostDelayedTask(
+          FROM_HERE,
+          base::BindOnce(&PasswordProtectionRequest::Cancel, GetWeakPtr(),
+                         true),
+          base::TimeDelta::FromMilliseconds(request_timeout_in_ms_));
 }
 
 void PasswordProtectionRequest::OnURLLoaderComplete(

components/safe_browsing/content/password_protection/password_protection_service.cc

@@ -27,8 +27,6 @@
 #include "components/safe_browsing/core/db/database_manager.h"
 #include "components/safe_browsing/core/features.h"
 #include "components/zoom/zoom_controller.h"
-#include "content/public/browser/browser_task_traits.h"
-#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/web_contents.h"
 #include "google_apis/google_api_keys.h"
@@ -36,7 +34,6 @@
 #include "net/base/url_util.h"
 #include "third_party/blink/public/common/page/page_zoom.h"
 
-using content::BrowserThread;
 using content::WebContents;
 using history::HistoryService;
 using password_manager::metrics_util::PasswordType;
@@ -386,12 +383,13 @@ void PasswordProtectionService::FillUserPopulation(
 void PasswordProtectionService::OnURLsDeleted(
     history::HistoryService* history_service,
     const history::DeletionInfo& deletion_info) {
-  content::GetUIThreadTaskRunner({})->PostTask(
-      FROM_HERE,
-      base::BindRepeating(&PasswordProtectionService::
-                              RemoveUnhandledSyncPasswordReuseOnURLsDeleted,
-                          GetWeakPtr(), deletion_info.IsAllHistory(),
-                          deletion_info.deleted_rows()));
+  GetTaskRunner(ThreadID::UI)
+      ->PostTask(
+          FROM_HERE,
+          base::BindRepeating(&PasswordProtectionService::
+                                  RemoveUnhandledSyncPasswordReuseOnURLsDeleted,
+                              GetWeakPtr(), deletion_info.IsAllHistory(),
+                              deletion_info.deleted_rows()));
 }
 
 void PasswordProtectionService::HistoryServiceBeingDeleted(

components/safe_browsing/core/common/thread_utils.h

@@ -5,6 +5,8 @@
 #ifndef COMPONENTS_SAFE_BROWSING_CORE_COMMON_THREAD_UTILS_H_
 #define COMPONENTS_SAFE_BROWSING_CORE_COMMON_THREAD_UTILS_H_
 
+#include "base/memory/scoped_refptr.h"
+#include "base/single_thread_task_runner.h"
 #include "base/task/task_traits.h"
 
 namespace safe_browsing {
@@ -31,6 +33,10 @@ bool CurrentlyOnThread(ThreadID thread_id) WARN_UNUSED_RESULT;
 // thread.
 base::TaskTraits CreateTaskTraits(ThreadID thread_id);
 
+// Callable on any thread. Returns the task runner associated with the given
+// identifier.
+scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner(ThreadID thread_id);
+
 }  // namespace safe_browsing
 
 #endif  // COMPONENTS_SAFE_BROWSING_CORE_COMMON_THREAD_UTILS_H_

components/safe_browsing/ios/thread_utils_ios.cc

@@ -4,6 +4,8 @@
 
 #include "components/safe_browsing/core/common/thread_utils.h"
 
+#include "base/notreached.h"
+#include "base/task/post_task.h"
 #include "ios/web/public/thread/web_task_traits.h"
 #include "ios/web/public/thread/web_thread.h"
 
@@ -31,4 +33,8 @@ base::TaskTraits CreateTaskTraits(ThreadID thread_id) {
   return {WebThreadID(thread_id)};
 }
 
+scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner(ThreadID thread_id) {
+  return base::CreateSingleThreadTaskRunner(CreateTaskTraits(thread_id));
+}
+
 }  // namespace safe_browsing