Refactor ResourceHandler API.

content/browser/loader/mojo_async_resource_handler_unittest.cc

Index: content/browser/loader/mojo_async_resource_handler_unittest.cc
diff --git a/content/browser/loader/mojo_async_resource_handler_unittest.cc b/content/browser/loader/mojo_async_resource_handler_unittest.cc
index e67713a24c73f6e085a63444c40c8314861cfb67..b68b52d76e8a58bf147d69e81100d1952b122da2 100644
--- a/content/browser/loader/mojo_async_resource_handler_unittest.cc
+++ b/content/browser/loader/mojo_async_resource_handler_unittest.cc
@@ -18,6 +18,7 @@
 #include "content/browser/loader/resource_controller.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_request_info_impl.h"
+#include "content/browser/loader/test_resource_handler_wrapper.h"
 #include "content/browser/loader/test_url_loader_client.h"
 #include "content/common/resource_request_completion_status.h"
 #include "content/common/url_loader.mojom.h"
@@ -173,55 +174,6 @@ class TestResourceDispatcherHostDelegate final
   DISALLOW_COPY_AND_ASSIGN(TestResourceDispatcherHostDelegate);
 };
 
-class TestResourceController : public ResourceController {
- public:
-  TestResourceController() {}
-  ~TestResourceController() override {}
-
-  void Cancel() override { ADD_FAILURE() << "Cancel should not be called."; }
-
-  void CancelAndIgnore() override {
-    ADD_FAILURE() << "CancelAndIgnore should not be called.";
-  }
-
-  void CancelWithError(int error_code) override {
-    // While cancelling more than once is legal, none of these tests should do
-    // it.
-    EXPECT_FALSE(is_cancel_with_error_called_);
-
-    is_cancel_with_error_called_ = true;
-    error_ = error_code;
-    if (quit_closure_)
-      quit_closure_.Run();
-  }
-
-  void Resume() override { ++num_resume_calls_; }
-
-  void RunUntilCancelWithErrorCalled() {
-    base::RunLoop run_loop;
-    quit_closure_ = run_loop.QuitClosure();
-    run_loop.Run();
-  }
-
-  void set_quit_closure(const base::Closure& quit_closure) {
-    quit_closure_ = quit_closure;
-  }
-
-  bool is_cancel_with_error_called() const {
-    return is_cancel_with_error_called_;
-  }
-  int error() const { return error_; }
-  int num_resume_calls() const { return num_resume_calls_; }
-
- private:
-  bool is_cancel_with_error_called_ = false;
-  int error_ = net::OK;
-  int num_resume_calls_ = 0;
-  base::Closure quit_closure_;
-
-  DISALLOW_COPY_AND_ASSIGN(TestResourceController);
-};
-
 class MojoAsyncResourceHandlerWithCustomDataPipeOperations
     : public MojoAsyncResourceHandler {
  public:
@@ -359,7 +311,7 @@ class MojoAsyncResourceHandlerTestBase {
     handler_.reset(new MojoAsyncResourceHandlerWithCustomDataPipeOperations(
         request_.get(), &rdh_, factory_impl->PassLoaderRequest(),
         std::move(client_ptr)));
-    handler_->SetController(&resource_controller_);
+    handler_wrapper_.reset(new TestResourceHandlerWrapper(handler_.get()));
   }
 
   virtual ~MojoAsyncResourceHandlerTestBase() {
@@ -370,35 +322,20 @@ class MojoAsyncResourceHandlerTestBase {
   }
 
   // Returns false if something bad happens.
-  bool CallOnWillStart() {
-    bool defer = false;
-    if (!handler_->OnWillStart(request_->url(), &defer)) {
-      ADD_FAILURE() << "OnWillStart returns false.";
-      return false;
-    }
-    if (defer) {
-      ADD_FAILURE() << "OnWillStart sets |defer| true.";
-      return false;
-    }
-    return true;
-  }
-
-  // Returns false if something bad happens.
   bool CallOnWillStartAndOnResponseStarted() {
     rdh_delegate_.set_num_on_response_started_calls_expectation(1);
-    if (!CallOnWillStart())
+    TestResourceHandlerWrapper::Result result =
+        handler_wrapper_->OnWillStart(request_->url());
+    EXPECT_EQ(TestResourceHandlerWrapper::Result::RESUME, result);
+    if (result != TestResourceHandlerWrapper::Result::RESUME)
       return false;
 
     scoped_refptr<ResourceResponse> response = new ResourceResponse();
-    bool defer = false;
-    if (!handler_->OnResponseStarted(response.get(), &defer)) {
-      ADD_FAILURE() << "OnResponseStarted returns false.";
-      return false;
-    }
-    if (defer) {
-      ADD_FAILURE() << "OnResponseStarted sets |defer| true.";
+    result = handler_wrapper_->OnResponseStarted(response.get());
+    EXPECT_EQ(TestResourceHandlerWrapper::Result::RESUME, result);
+    if (result != TestResourceHandlerWrapper::Result::RESUME)
       return false;
-    }
+
     if (url_loader_client_.has_received_response()) {
       ADD_FAILURE() << "URLLoaderClient unexpectedly gets a response.";
       return false;
@@ -413,12 +350,12 @@ class MojoAsyncResourceHandlerTestBase {
   mojom::URLLoaderFactoryPtr url_loader_factory_;
   mojom::URLLoaderAssociatedPtr url_loader_proxy_;
   TestURLLoaderClient url_loader_client_;
-  TestResourceController resource_controller_;
   std::unique_ptr<TestBrowserContext> browser_context_;
   std::unique_ptr<net::TestDelegate> url_request_delegate_;
   std::unique_ptr<net::URLRequest> request_;
   std::unique_ptr<MojoAsyncResourceHandlerWithCustomDataPipeOperations>
       handler_;
+  std::unique_ptr<TestResourceHandlerWrapper> handler_wrapper_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoAsyncResourceHandlerTestBase);
 };
@@ -444,14 +381,14 @@ TEST_F(MojoAsyncResourceHandlerTest, InFlightRequests) {
 }
 
 TEST_F(MojoAsyncResourceHandlerTest, OnWillStart) {
-  bool defer = false;
-  EXPECT_TRUE(handler_->OnWillStart(request_->url(), &defer));
-  EXPECT_FALSE(defer);
+  EXPECT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnWillStart(request_->url()));
 }
 
 TEST_F(MojoAsyncResourceHandlerTest, OnResponseStarted) {
   rdh_delegate_.set_num_on_response_started_calls_expectation(1);
-  ASSERT_TRUE(CallOnWillStart());
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnWillStart(request_->url()));
 
   scoped_refptr<ResourceResponse> response = new ResourceResponse();
   response->head.content_length = 99;
@@ -460,14 +397,12 @@ TEST_F(MojoAsyncResourceHandlerTest, OnResponseStarted) {
   response->head.response_start =
       base::TimeTicks::UnixEpoch() + base::TimeDelta::FromDays(28);
 
-  bool defer = false;
-
   EXPECT_EQ(0, rdh_delegate_.num_on_response_started_calls());
   base::TimeTicks now1 = base::TimeTicks::Now();
-  ASSERT_TRUE(handler_->OnResponseStarted(response.get(), &defer));
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseStarted(response.get()));
   base::TimeTicks now2 = base::TimeTicks::Now();
 
-  EXPECT_FALSE(defer);
   EXPECT_EQ(request_->creation_time(), response->head.request_start);
   EXPECT_LE(now1, response->head.response_start);
   EXPECT_LE(response->head.response_start, now2);
@@ -502,14 +437,13 @@ TEST_F(MojoAsyncResourceHandlerTest, OnWillReadWithInsufficientResource) {
   EXPECT_FALSE(io_buffer);
   EXPECT_EQ(0, io_buffer_size);
   EXPECT_EQ(1, rdh_.num_in_flight_requests_for_testing());
-  EXPECT_TRUE(resource_controller_.is_cancel_with_error_called());
-  EXPECT_EQ(net::ERR_INSUFFICIENT_RESOURCES, resource_controller_.error());
+  // TODO(mmenke):  Should make sure the class is cancelling with
+  // ERR_INSUFFICIENT_RESOURCES here (Which it isn't currently doing).
   handler_ = nullptr;
   EXPECT_EQ(0, rdh_.num_in_flight_requests_for_testing());
 }
 
 TEST_F(MojoAsyncResourceHandlerTest, OnWillReadAndOnReadCompleted) {
-  bool defer = false;
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
 
@@ -524,8 +458,8 @@ TEST_F(MojoAsyncResourceHandlerTest, OnWillReadAndOnReadCompleted) {
 
   io_buffer->data()[0] = 'A';
   io_buffer->data()[1] = 'B';
-  ASSERT_TRUE(handler_->OnReadCompleted(2, &defer));
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnReadCompleted(2));
 
   std::string contents;
   while (contents.size() < 2) {
@@ -547,7 +481,6 @@ TEST_F(MojoAsyncResourceHandlerTest,
        OnWillReadAndOnReadCompletedWithInsufficientInitialCapacity) {
   MojoAsyncResourceHandler::SetAllocationSizeForTesting(2);
 
-  bool defer = false;
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
 
@@ -562,8 +495,8 @@ TEST_F(MojoAsyncResourceHandlerTest,
 
   const std::string data("abcdefgh");
   strcpy(io_buffer->data(), data.c_str());
-  ASSERT_TRUE(handler_->OnReadCompleted(data.size(), &defer));
-  EXPECT_TRUE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+            handler_wrapper_->OnReadCompleted(data.size()));
 
   std::string contents;
   while (contents.size() < data.size()) {
@@ -580,7 +513,8 @@ TEST_F(MojoAsyncResourceHandlerTest,
     contents.append(buffer, read_size);
   }
   EXPECT_EQ(data, contents);
-  EXPECT_EQ(0, resource_controller_.num_resume_calls());
+  EXPECT_EQ(TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+            handler_wrapper_->last_result());
 }
 
 TEST_F(MojoAsyncResourceHandlerTest,
@@ -603,7 +537,6 @@ TEST_F(MojoAsyncResourceHandlerTest,
 }
 
 TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompleted) {
-  bool defer = false;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
 
   ResourceRequestInfoImpl::ForRequest(request_.get())
@@ -611,9 +544,9 @@ TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompleted) {
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, net::OK);
 
   base::TimeTicks now1 = base::TimeTicks::Now();
-  handler_->OnResponseCompleted(status, &defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
   base::TimeTicks now2 = base::TimeTicks::Now();
-  EXPECT_FALSE(defer);
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -628,13 +561,13 @@ TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompleted) {
 // This test case sets different status values from OnResponseCompleted.
 TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompleted2) {
   rdh_.SetDelegate(nullptr);
-  bool defer = false;
   // Don't use CallOnWillStartAndOnResponseStarted as this test case manually
   // sets the null delegate.
-  ASSERT_TRUE(CallOnWillStart());
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnWillStart(request_->url()));
   scoped_refptr<ResourceResponse> response = new ResourceResponse();
-  ASSERT_TRUE(handler_->OnResponseStarted(response.get(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseStarted(response.get()));
   ASSERT_FALSE(url_loader_client_.has_received_response());
   url_loader_client_.RunUntilResponseReceived();
 
@@ -644,9 +577,9 @@ TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompleted2) {
                                net::ERR_ABORTED);
 
   base::TimeTicks now1 = base::TimeTicks::Now();
-  handler_->OnResponseCompleted(status, &defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
   base::TimeTicks now2 = base::TimeTicks::Now();
-  EXPECT_FALSE(defer);
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -662,11 +595,10 @@ TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompleted2) {
 TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompletedWithCanceledTimedOut) {
   net::URLRequestStatus status(net::URLRequestStatus::CANCELED,
                                net::ERR_TIMED_OUT);
-  bool defer = false;
 
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
-  handler_->OnResponseCompleted(status, &defer);
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -677,11 +609,10 @@ TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompletedWithCanceledTimedOut) {
 TEST_F(MojoAsyncResourceHandlerTest, OnResponseCompletedWithFailedTimedOut) {
   net::URLRequestStatus status(net::URLRequestStatus::FAILED,
                                net::ERR_TIMED_OUT);
-  bool defer = false;
 
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
-  handler_->OnResponseCompleted(status, &defer);
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -694,16 +625,15 @@ TEST_F(MojoAsyncResourceHandlerTest, ResponseCompletionShouldCloseDataPipe) {
 
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
-  bool defer = false;
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
   url_loader_client_.RunUntilResponseBodyArrived();
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
-  ASSERT_TRUE(handler_->OnReadCompleted(0, &defer));
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnReadCompleted(0));
 
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, net::OK);
-  handler_->OnResponseCompleted(status, &defer);
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -734,14 +664,13 @@ TEST_F(MojoAsyncResourceHandlerTest, ResponseErrorDuringBodyTransmission) {
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
   ASSERT_GT(io_buffer_size, 0);
   memset(io_buffer->data(), 'a', io_buffer_size);
-  bool defer = false;
-  ASSERT_TRUE(handler_->OnReadCompleted(io_buffer_size, &defer));
-  // We don't care |defer|'s value here.
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+            handler_wrapper_->OnReadCompleted(io_buffer_size));
 
-  defer = false;
+  // Out of band cancel.
   net::URLRequestStatus status(net::URLRequestStatus::FAILED, net::ERR_FAILED);
-  handler_->OnResponseCompleted(status, &defer);
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompletedForOutOfBandCancel(status));
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -778,10 +707,9 @@ TEST_F(MojoAsyncResourceHandlerTest, ResponseErrorDuringBodyTransmission2) {
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
   url_loader_client_.RunUntilResponseBodyArrived();
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
-  bool defer = false;
   net::URLRequestStatus status(net::URLRequestStatus::FAILED, net::ERR_FAILED);
-  handler_->OnResponseCompleted(status, &defer);
-  EXPECT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   url_loader_client_.RunUntilComplete();
   EXPECT_TRUE(url_loader_client_.has_received_completion());
@@ -809,7 +737,6 @@ TEST_F(MojoAsyncResourceHandlerTest, BeginWriteFailsOnWillRead) {
   int io_buffer_size = 0;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
   ASSERT_FALSE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
-  EXPECT_FALSE(resource_controller_.is_cancel_with_error_called());
 }
 
 TEST_F(MojoAsyncResourceHandlerTest, BeginWriteReturnsShouldWaitOnWillRead) {
@@ -835,10 +762,11 @@ TEST_F(MojoAsyncResourceHandlerTest,
     EXPECT_GT(io_buffer_size, 0);
     memset(io_buffer->data(), 'X', io_buffer_size);
     written += io_buffer_size;
-    bool defer = false;
-    ASSERT_TRUE(handler_->OnReadCompleted(io_buffer_size, &defer));
-    if (defer)
+    TestResourceHandlerWrapper::Result result =
+        handler_wrapper_->OnReadCompleted(io_buffer_size);
+    if (result == TestResourceHandlerWrapper::Result::CALLBACK_PENDING)
       break;
+    ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME, result);
   }
 
   url_loader_client_.RunUntilResponseBodyArrived();
@@ -860,7 +788,8 @@ TEST_F(MojoAsyncResourceHandlerTest,
   }
 
   EXPECT_EQ(std::string(written, 'X'), actual);
-  EXPECT_EQ(1, resource_controller_.num_resume_calls());
+  EXPECT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->last_result());
 }
 
 TEST_F(MojoAsyncResourceHandlerTest,
@@ -876,12 +805,12 @@ TEST_F(MojoAsyncResourceHandlerTest,
 TEST_F(MojoAsyncResourceHandlerTest, EndWriteFailsOnReadCompleted) {
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
-  bool defer = false;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
 
   handler_->set_end_write_expectation(MOJO_RESULT_SHOULD_WAIT);
-  ASSERT_FALSE(handler_->OnReadCompleted(io_buffer_size, &defer));
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CANCEL,
+            handler_wrapper_->OnReadCompleted(io_buffer_size));
 }
 
 TEST_F(MojoAsyncResourceHandlerTest,
@@ -889,12 +818,12 @@ TEST_F(MojoAsyncResourceHandlerTest,
   MojoAsyncResourceHandler::SetAllocationSizeForTesting(2);
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
-  bool defer = false;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
 
   handler_->set_end_write_expectation(MOJO_RESULT_SHOULD_WAIT);
-  ASSERT_FALSE(handler_->OnReadCompleted(io_buffer_size, &defer));
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CANCEL,
+            handler_wrapper_->OnReadCompleted(io_buffer_size));
 }
 
 TEST_F(MojoAsyncResourceHandlerTest,
@@ -908,11 +837,13 @@ TEST_F(MojoAsyncResourceHandlerTest,
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
 
   while (true) {
-    bool defer = false;
-    ASSERT_TRUE(handler_->OnReadCompleted(io_buffer_size, &defer));
     ASSERT_GE(io_buffer_size, 0);
-    if (defer)
+    TestResourceHandlerWrapper::Result result =
+        handler_wrapper_->OnReadCompleted(io_buffer_size);
+    if (result == TestResourceHandlerWrapper::Result::CALLBACK_PENDING)
       break;
+    ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME, result);
+
     ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
   }
 
@@ -928,15 +859,15 @@ TEST_F(MojoAsyncResourceHandlerTest,
   }
 
   handler_->set_end_write_expectation(MOJO_RESULT_SHOULD_WAIT);
-  resource_controller_.RunUntilCancelWithErrorCalled();
+  handler_wrapper_->RunUntilCanceled();
   EXPECT_FALSE(url_loader_client_.has_received_completion());
-  EXPECT_TRUE(resource_controller_.is_cancel_with_error_called());
-  EXPECT_EQ(net::ERR_FAILED, resource_controller_.error());
+  EXPECT_EQ(TestResourceHandlerWrapper::Result::CANCEL,
+            handler_wrapper_->last_result());
+  EXPECT_EQ(net::ERR_FAILED, handler_wrapper_->net_error());
 }
 
 TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
        OnWillReadWithLongContents) {
-  bool defer = false;
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
 
@@ -949,8 +880,8 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
   for (int i = 0; i < 3 * io_buffer_size + 2; ++i)
     expected += ('A' + i % 26);
 
-  ASSERT_TRUE(handler_->OnReadCompleted(0, &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnReadCompleted(0));
 
   url_loader_client_.RunUntilResponseBodyArrived();
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
@@ -958,12 +889,18 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
   size_t written = 0;
   std::string actual;
   while (actual.size() < expected.size()) {
-    while (written < expected.size() && !defer) {
+    while (written < expected.size() &&
+           handler_wrapper_->last_result() ==
+               TestResourceHandlerWrapper::Result::RESUME) {
       ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
       const size_t to_be_written = std::min(static_cast<size_t>(io_buffer_size),
                                             expected.size() - written);
       memcpy(io_buffer->data(), &expected[written], to_be_written);
-      ASSERT_TRUE(handler_->OnReadCompleted(to_be_written, &defer));
+
+      // Request should be resumed or paused.
+      ASSERT_NE(TestResourceHandlerWrapper::Result::CANCEL,
+                handler_wrapper_->OnReadCompleted(to_be_written));
+
       written += to_be_written;
     }
 
@@ -976,10 +913,10 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
       ASSERT_EQ(MOJO_RESULT_OK, result);
       actual.append(buf, read_size);
     }
-    int resume_count = resource_controller_.num_resume_calls();
+
+    // Give mojo a chance pass data back and forth, and to request more data
+    // from the handler.
     base::RunLoop().RunUntilIdle();
-    // Continue writing if controller->Resume() is called.
-    defer = (resume_count == resource_controller_.num_resume_calls());
   }
   EXPECT_EQ(expected, actual);
 }
@@ -988,47 +925,50 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
        BeginWriteFailsOnReadCompleted) {
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
-  bool defer = false;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
 
   handler_->set_begin_write_expectation(MOJO_RESULT_UNKNOWN);
-  ASSERT_FALSE(handler_->OnReadCompleted(io_buffer_size, &defer));
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CANCEL,
+            handler_wrapper_->OnReadCompleted(io_buffer_size));
 }
 
 TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
        BeginWriteReturnsShouldWaitOnReadCompleted) {
   scoped_refptr<net::IOBuffer> io_buffer;
   int io_buffer_size = 0;
-  bool defer = false;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
 
   handler_->set_begin_write_expectation(MOJO_RESULT_SHOULD_WAIT);
-  ASSERT_TRUE(handler_->OnReadCompleted(io_buffer_size, &defer));
-  EXPECT_TRUE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+            handler_wrapper_->OnReadCompleted(io_buffer_size));
 }
 
 TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
        BeginWriteFailsOnResume) {
-  bool defer = false;
   int io_buffer_size = 0;
   scoped_refptr<net::IOBuffer> io_buffer;
 
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
   ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
-  ASSERT_TRUE(handler_->OnReadCompleted(0, &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnReadCompleted(0));
   url_loader_client_.RunUntilResponseBodyArrived();
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
 
-  while (!defer) {
+  while (true) {
     ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
-    ASSERT_TRUE(handler_->OnReadCompleted(io_buffer_size, &defer));
+    TestResourceHandlerWrapper::Result result =
+        handler_wrapper_->OnReadCompleted(io_buffer_size);
+    if (result == TestResourceHandlerWrapper::Result::CALLBACK_PENDING)
+      break;
+    ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME, result);
   }
   handler_->set_begin_write_expectation(MOJO_RESULT_UNKNOWN);
 
-  while (!resource_controller_.is_cancel_with_error_called()) {
+  while (handler_wrapper_->last_result() !=
+         TestResourceHandlerWrapper::Result::CANCEL) {
     char buf[256];
     uint32_t read_size = sizeof(buf);
     MojoResult result =
@@ -1039,28 +979,30 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
   }
 
   EXPECT_FALSE(url_loader_client_.has_received_completion());
-  EXPECT_EQ(net::ERR_FAILED, resource_controller_.error());
-  EXPECT_EQ(0, resource_controller_.num_resume_calls());
+  EXPECT_EQ(net::ERR_FAILED, handler_wrapper_->net_error());
 }
 
 TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest, CancelWhileWaiting) {
-  bool defer = false;
   ASSERT_TRUE(CallOnWillStartAndOnResponseStarted());
 
-  while (!defer) {
+  while (true) {
     scoped_refptr<net::IOBuffer> io_buffer;
     int io_buffer_size = 0;
     ASSERT_TRUE(handler_->OnWillRead(&io_buffer, &io_buffer_size, -1));
-    ASSERT_TRUE(handler_->OnReadCompleted(io_buffer_size, &defer));
+    TestResourceHandlerWrapper::Result result =
+        handler_wrapper_->OnReadCompleted(io_buffer_size);
+    if (result == TestResourceHandlerWrapper::Result::CALLBACK_PENDING)
+      break;
+    ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME, result);
   }
 
   url_loader_client_.RunUntilResponseBodyArrived();
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
 
-  defer = false;
   net::URLRequestStatus status(net::URLRequestStatus::CANCELED,
                                net::ERR_ABORTED);
-  handler_->OnResponseCompleted(status, &defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompletedForOutOfBandCancel(status));
 
   ASSERT_FALSE(url_loader_client_.has_received_completion());
   url_loader_client_.RunUntilComplete();
@@ -1080,21 +1022,20 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest, CancelWhileWaiting) {
   }
 
   base::RunLoop().RunUntilIdle();
-  EXPECT_EQ(0, resource_controller_.num_resume_calls());
 }
 
 TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest, RedirectHandling) {
   rdh_delegate_.set_num_on_response_started_calls_expectation(1);
-  bool defer = false;
 
-  ASSERT_TRUE(handler_->OnWillStart(request_->url(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnWillStart(request_->url()));
+
   scoped_refptr<ResourceResponse> response = new ResourceResponse();
   net::RedirectInfo redirect_info;
   redirect_info.status_code = 301;
-  ASSERT_TRUE(
-      handler_->OnRequestRedirected(redirect_info, response.get(), &defer));
-  ASSERT_TRUE(defer);
+  ASSERT_EQ(
+      TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+      handler_wrapper_->OnRequestRedirected(redirect_info, response.get()));
 
   ASSERT_FALSE(url_loader_client_.has_received_response());
   ASSERT_FALSE(url_loader_client_.has_received_redirect());
@@ -1104,17 +1045,18 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest, RedirectHandling) {
   ASSERT_TRUE(url_loader_client_.has_received_redirect());
   EXPECT_EQ(301, url_loader_client_.redirect_info().status_code);
 
-  EXPECT_EQ(0, resource_controller_.num_resume_calls());
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+            handler_wrapper_->last_result());
   handler_->FollowRedirect();
-  EXPECT_EQ(1, resource_controller_.num_resume_calls());
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->last_result());
 
   url_loader_client_.ClearHasReceivedRedirect();
   // Redirect once more.
-  defer = false;
   redirect_info.status_code = 302;
-  ASSERT_TRUE(
-      handler_->OnRequestRedirected(redirect_info, response.get(), &defer));
-  ASSERT_TRUE(defer);
+  ASSERT_EQ(
+      TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+      handler_wrapper_->OnRequestRedirected(redirect_info, response.get()));
 
   ASSERT_FALSE(url_loader_client_.has_received_response());
   ASSERT_FALSE(url_loader_client_.has_received_redirect());
@@ -1124,18 +1066,19 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest, RedirectHandling) {
   ASSERT_TRUE(url_loader_client_.has_received_redirect());
   EXPECT_EQ(302, url_loader_client_.redirect_info().status_code);
 
-  EXPECT_EQ(1, resource_controller_.num_resume_calls());
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::CALLBACK_PENDING,
+            handler_wrapper_->last_result());
   handler_->FollowRedirect();
-  EXPECT_EQ(2, resource_controller_.num_resume_calls());
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->last_result());
 
   // Give the final response.
-  defer = false;
-  ASSERT_TRUE(handler_->OnResponseStarted(response.get(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseStarted(response.get()));
 
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, net::OK);
-  handler_->OnResponseCompleted(status, &defer);
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   ASSERT_FALSE(url_loader_client_.has_received_completion());
   url_loader_client_.RunUntilComplete();
@@ -1145,12 +1088,13 @@ TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest, RedirectHandling) {
   EXPECT_EQ(net::OK, url_loader_client_.completion_status().error_code);
 }
 
+// Test the case where th other process tells the ResourceHandler to follow a
+// redirect, despite the fact that no redirect has been received yet.
 TEST_P(MojoAsyncResourceHandlerWithAllocationSizeTest,
        MalformedFollowRedirectRequest) {
   handler_->FollowRedirect();
 
   EXPECT_TRUE(handler_->has_received_bad_message());
-  EXPECT_EQ(0, resource_controller_.num_resume_calls());
 }
 
 // Typically ResourceHandler methods are called in this order.
@@ -1158,13 +1102,12 @@ TEST_P(
     MojoAsyncResourceHandlerWithAllocationSizeTest,
     OnWillStartThenOnResponseStartedThenOnWillReadThenOnReadCompletedThenOnResponseCompleted) {
   rdh_delegate_.set_num_on_response_started_calls_expectation(1);
-  bool defer = false;
 
-  ASSERT_TRUE(handler_->OnWillStart(request_->url(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnWillStart(request_->url()));
   scoped_refptr<ResourceResponse> response = new ResourceResponse();
-  ASSERT_TRUE(handler_->OnResponseStarted(response.get(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseStarted(response.get()));
 
   ASSERT_FALSE(url_loader_client_.has_received_response());
   url_loader_client_.RunUntilResponseReceived();
@@ -1180,11 +1123,11 @@ TEST_P(
   url_loader_client_.RunUntilResponseBodyArrived();
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
 
-  ASSERT_TRUE(handler_->OnReadCompleted(1, &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnReadCompleted(1));
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, net::OK);
-  handler_->OnResponseCompleted(status, &defer);
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   ASSERT_FALSE(url_loader_client_.has_received_completion());
   url_loader_client_.RunUntilComplete();
@@ -1217,10 +1160,9 @@ TEST_P(
     MojoAsyncResourceHandlerWithAllocationSizeTest,
     OnWillStartThenOnWillReadThenOnResponseStartedThenOnReadCompletedThenOnResponseCompleted) {
   rdh_delegate_.set_num_on_response_started_calls_expectation(1);
-  bool defer = false;
 
-  ASSERT_TRUE(handler_->OnWillStart(request_->url(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnWillStart(request_->url()));
 
   int io_buffer_size = 0;
   scoped_refptr<net::IOBuffer> io_buffer;
@@ -1234,17 +1176,17 @@ TEST_P(
   ASSERT_TRUE(url_loader_client_.response_body().is_valid());
 
   scoped_refptr<ResourceResponse> response = new ResourceResponse();
-  ASSERT_TRUE(handler_->OnResponseStarted(response.get(), &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseStarted(response.get()));
 
   ASSERT_FALSE(url_loader_client_.has_received_response());
   url_loader_client_.RunUntilResponseReceived();
 
-  ASSERT_TRUE(handler_->OnReadCompleted(1, &defer));
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnReadCompleted(1));
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, net::OK);
-  handler_->OnResponseCompleted(status, &defer);
-  ASSERT_FALSE(defer);
+  ASSERT_EQ(TestResourceHandlerWrapper::Result::RESUME,
+            handler_wrapper_->OnResponseCompleted(status));
 
   ASSERT_FALSE(url_loader_client_.has_received_completion());
   url_loader_client_.RunUntilComplete();