Renderer reading side of gamepad

content/browser/gamepad/gamepad_provider_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/memory/scoped_ptr.h"
 #include "base/process_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/system_monitor/system_monitor.h"
 #include "content/browser/gamepad/gamepad_provider.h"
 #include "content/common/gamepad_messages.h"
@@ skipping 46 matching lines @@
 };
 
 TEST_F(GamepadProviderTest, BasicStartStop) {
   gamepad::Provider* provider = CreateProvider();
   provider->Start();
   provider->Stop();
   // Just ensure that there's no asserts on startup, shutdown, or destroy.
 }
 
 // http://crbug.com/105348
-TEST_F(GamepadProviderTest, FLAKY_PollingAccess) {
+TEST_F(GamepadProviderTest, PollingAccess) {
   using namespace gamepad;
 
   Provider* provider = CreateProvider();
   provider->Start();
 
   WebKit::WebGamepads test_data;
   test_data.length = 1;
   test_data.items[0].connected = true;
   test_data.items[0].timestamp = 0;
   test_data.items[0].buttonsLength = 1;
@@ skipping 10 matching lines @@
   // Renderer-side, pull data out of poll buffer.
   base::SharedMemoryHandle handle =
       provider->GetRendererSharedMemoryHandle(base::GetCurrentProcessHandle());
   scoped_ptr<base::SharedMemory> shared_memory(
       new base::SharedMemory(handle, true));
   EXPECT_TRUE(shared_memory->Map(sizeof(GamepadHardwareBuffer)));
   void* mem = shared_memory->memory();
 
   GamepadHardwareBuffer* hwbuf = static_cast<GamepadHardwareBuffer*>(mem);
   // See gamepad_hardware_buffer.h for details on the read discipline.
-  base::subtle::Atomic32 start, end;
   WebKit::WebGamepads output;
-  int contention_count;
 
-  // Here we're attempting to test the read discipline during contention. If
-  // we fail to read this many times, then the read thread is starving, and we
-  // should fail the test.
-  for (contention_count = 0; contention_count < 1000; ++contention_count) {
-    end = base::subtle::Acquire_Load(&hwbuf->end_marker);
+  base::subtle::Atomic32 version;
+  do {
+    version = hwbuf->sequence.ReadBegin();
     memcpy(&output, &hwbuf->buffer, sizeof(output));
-    start = base::subtle::Acquire_Load(&hwbuf->start_marker);
-    if (start == end)
-        break;
-    base::PlatformThread::YieldCurrentThread();
-  }
-  EXPECT_GT(1000, contention_count);
+  } while (hwbuf->sequence.ReadRetry(version));
+
   EXPECT_EQ(1u, output.length);
   EXPECT_EQ(1u, output.items[0].buttonsLength);
   EXPECT_EQ(1.f, output.items[0].buttons[0]);
   EXPECT_EQ(2u, output.items[0].axesLength);
   EXPECT_EQ(-1.f, output.items[0].axes[0]);
   EXPECT_EQ(0.5f, output.items[0].axes[1]);
 
   provider->Stop();
 }
 
 }  // namespace