[TaskEnvironment] Migrate iOS's TestWebThreadBundle too

This is the iOS equivalent of
https://chromium-review.googlesource.com/c/chromium/src/+/1747171

Required to facilitate the mass-rename of "thread_bundle" variables.

R=rohitrao@chromium.org

Bug: 992483
Change-Id: I244370aa92eb53933cfe4076209b84b58b658504
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1757366Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Auto-Submit: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688256}

ios/web/public/test/test_web_thread.h

@@ -20,7 +20,7 @@ namespace web {
 class WebSubThread;
 class WebThreadImpl;
 
-// DEPRECATED: use TestWebThreadBundle instead.
+// DEPRECATED: use WebTaskEnvironment instead.
 // A WebThread for unit tests; this lets unit tests outside of web create
 // WebThread instances.
 class TestWebThread {

ios/web/public/test/test_web_thread_bundle.h

@@ -7,27 +7,31 @@
 
 #include "base/test/scoped_task_environment.h"
 
-// TestWebThreadBundle is a convenience class for creating a set of
-// TestWebThreads and a thread pool in unit tests. For most tests, it is
-// sufficient to just instantiate the TestWebThreadBundle as a member variable.
-// It is a good idea to put the TestWebThreadBundle as the first member variable
-// in test classes, so it is destroyed last, and the test threads always exist
-// from the perspective of other classes.
+// TODO(crbug.com/992483): Rename this header to web_task_environment.h and
+// migrate all users.
+//
+// WebTaskEnvironment is the iOS equivalent of content::BrowserTaskEnvironment.
+//
+// It's is a convenience class for creating a set of TestWebThreads and a thread
+// pool in unit tests. For most tests, it is sufficient to just instantiate the
+// WebTaskEnvironment as a member variable. It is a good idea to put the
+// WebTaskEnvironment as the first member variable in test classes, so it is
+// destroyed last, and the test threads always exist from the perspective of
+// other classes.
 //
 // By default, all of the created TestWebThreads will be backed by a single
 // shared MessageLoop. If a test truly needs separate threads, it can do so by
 // passing the appropriate combination of option values during the
-// TestWebThreadBundle construction.
+// WebTaskEnvironment construction.
 //
 // To synchronously run tasks posted to TestWebThreads that use the shared
 // MessageLoop, call RunLoop::Run/RunUntilIdle() on the thread where the
-// TestWebThreadBundle lives. The destructor of TestWebThreadBundle runs
-// remaining TestWebThreads tasks and remaining BLOCK_SHUTDOWN thread pool
-// tasks.
+// WebTaskEnvironment lives. The destructor of WebTaskEnvironment runs remaining
+// TestWebThreads tasks and remaining BLOCK_SHUTDOWN thread pool tasks.
 //
-// Some tests using the IO thread expect a MessageLoopForIO. Passing
-// IO_MAINLOOP will use a MessageLoopForIO for the main MessageLoop.
-// Most of the time, this avoids needing to use a REAL_IO_THREAD.
+// Some tests using the IO thread expect a MessageLoopForIO. Passing IO_MAINLOOP
+// will use a MessageLoopForIO for the main MessageLoop. Most of the time, this
+// avoids needing to use a REAL_IO_THREAD.
 
 #include <memory>
 
@@ -41,7 +45,7 @@ namespace web {
 
 class TestWebThread;
 
-class TestWebThreadBundle : public base::test::TaskEnvironment {
+class WebTaskEnvironment : public base::test::TaskEnvironment {
  public:
   // Used to specify the type of MessageLoop that backs the UI thread, and
   // which of the named WebThreads should be backed by a real
@@ -52,9 +56,9 @@ class TestWebThreadBundle : public base::test::TaskEnvironment {
     REAL_IO_THREAD = 1 << 1,
   };
 
-  explicit TestWebThreadBundle(int options = Options::DEFAULT);
+  explicit WebTaskEnvironment(int options = Options::DEFAULT);
 
-  ~TestWebThreadBundle() override;
+  ~WebTaskEnvironment() override;
 
  private:
   void Init(int options);
@@ -62,7 +66,13 @@ class TestWebThreadBundle : public base::test::TaskEnvironment {
   std::unique_ptr<TestWebThread> ui_thread_;
   std::unique_ptr<TestWebThread> io_thread_;
 
-  DISALLOW_COPY_AND_ASSIGN(TestWebThreadBundle);
+  DISALLOW_COPY_AND_ASSIGN(WebTaskEnvironment);
+};
+
+// TODO(crbug.com/992483): Mass migrate users and remove this.
+class TestWebThreadBundle : public WebTaskEnvironment {
+ public:
+  using WebTaskEnvironment::WebTaskEnvironment;
 };
 
 }  // namespace web

ios/web/test/test_web_thread_bundle.cc

@@ -12,13 +12,13 @@
 
 namespace web {
 
-TestWebThreadBundle::TestWebThreadBundle(int options)
+WebTaskEnvironment::WebTaskEnvironment(int options)
     : base::test::TaskEnvironment(options == IO_MAINLOOP ? MainThreadType::IO
                                                          : MainThreadType::UI) {
   Init(options);
 }
 
-TestWebThreadBundle::~TestWebThreadBundle() {
+WebTaskEnvironment::~WebTaskEnvironment() {
   // To ensure a clean teardown, each thread's message loop must be flushed
   // just before the thread is destroyed. But stopping a fake thread does not
   // automatically flush the message loop, so do it manually.
@@ -40,13 +40,13 @@ TestWebThreadBundle::~TestWebThreadBundle() {
   WebThreadImpl::ResetTaskExecutorForTesting();
 }
 
-void TestWebThreadBundle::Init(int options) {
+void WebTaskEnvironment::Init(int options) {
   WebThreadImpl::CreateTaskExecutor();
 
   ui_thread_ =
       std::make_unique<TestWebThread>(WebThread::UI, GetMainThreadTaskRunner());
 
-  if (options & TestWebThreadBundle::REAL_IO_THREAD) {
+  if (options & WebTaskEnvironment::REAL_IO_THREAD) {
     io_thread_ = std::make_unique<TestWebThread>(WebThread::IO);
     io_thread_->StartIOThread();
   } else {