Pepper gamepad support

BUG=79098


Review URL: http://codereview.chromium.org/9085027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117077 0039d316-1c4b-4281-b951-d872f2087c98

20 files changed, 505 insertions, 8 deletions

diff --git a/content/renderer/pepper_plugin_delegate_impl.cc b/content/renderer/pepper_plugin_delegate_impl.cc
index 793543a..8bc1fb8 100644
--- a/content/renderer/pepper_plugin_delegate_impl.cc
+++ b/content/renderer/pepper_plugin_delegate_impl.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -31,6 +31,7 @@
 #include "content/common/view_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/renderer/content_renderer_client.h"
+#include "content/renderer/gamepad_shared_memory_reader.h"
 #include "content/renderer/gpu/command_buffer_proxy.h"
 #include "content/renderer/gpu/gpu_channel_host.h"
 #include "content/renderer/gpu/renderer_gl_context.h"
@@ -2035,6 +2036,12 @@ bool PepperPluginDelegateImpl::IsInFullscreenMode() {
   return render_view_->is_fullscreen();
 }
 
+void PepperPluginDelegateImpl::SampleGamepads(WebKit::WebGamepads* data) {
+  if (!gamepad_shared_memory_reader_.get())
+    gamepad_shared_memory_reader_.reset(new content::GamepadSharedMemoryReader);
+  gamepad_shared_memory_reader_->SampleGamepads(*data);
+}
+
 bool PepperPluginDelegateImpl::IsPageVisible() const {
   return !render_view_->is_hidden();
 }
diff --git a/content/renderer/pepper_plugin_delegate_impl.h b/content/renderer/pepper_plugin_delegate_impl.h
index 2ef8fb7..22f5ab2 100644
--- a/content/renderer/pepper_plugin_delegate_impl.h
+++ b/content/renderer/pepper_plugin_delegate_impl.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -30,6 +30,10 @@ class FilePath;
 class PepperPluginDelegateImpl;
 class RenderViewImpl;
 
+namespace content {
+class GamepadSharedMemoryReader;
+}
+
 namespace gfx {
 class Point;
 class Rect;
@@ -50,6 +54,7 @@ class PluginModule;
 
 namespace WebKit {
 class WebFileChooserCompletion;
+class WebGamepads;
 class WebMouseEvent;
 struct WebCompositionUnderline;
 struct WebFileChooserParams;
@@ -385,6 +390,7 @@ class PepperPluginDelegateImpl
   virtual void DidReceiveMouseEvent(
       webkit::ppapi::PluginInstance* instance) OVERRIDE;
   virtual bool IsInFullscreenMode() OVERRIDE;
+  virtual void SampleGamepads(WebKit::WebGamepads* data) OVERRIDE;
   virtual bool IsPageVisible() const OVERRIDE;
 
   // RenderViewObserver implementation.
@@ -496,6 +502,8 @@ class PepperPluginDelegateImpl
   // when it is destroyed via InstanceDeleted().
   webkit::ppapi::PluginInstance* last_mouse_event_target_;
 
+  scoped_ptr<content::GamepadSharedMemoryReader> gamepad_shared_memory_reader_;
+
   DISALLOW_COPY_AND_ASSIGN(PepperPluginDelegateImpl);
 };
 
diff --git a/ppapi/api/dev/ppb_gamepad_dev.idl b/ppapi/api/dev/ppb_gamepad_dev.idl
new file mode 100644
index 0000000..209a21c
--- /dev/null
+++ b/ppapi/api/dev/ppb_gamepad_dev.idl
@@ -0,0 +1,87 @@
+/* Copyright (c) 2012 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.
+ */
+
+/**
+ * This file defines the <code>PPB_Gamepad_Dev</code> interface, which
+ * provides access to gamepad devices.
+ */
+
+label Chrome {
+  M18 = 0.1
+};
+
+/**
+ * The data for one gamepad device.
+ */
+struct PP_GamepadData_Dev {
+    /**
+     * Is there a gamepad connected at this index? If this is false, no other
+     * data in this structure is valid.
+     */
+    char connected;
+
+    /**
+     * String identifier for the type of device/manufacturer.
+     */
+    uint16_t[128] id;
+
+    /**
+     * Monotonically increasing value that is incremented when the data have
+     * been updated.
+     */
+    uint64_t timestamp;
+
+    /**
+     * Number of valid elements in the |axes| array.
+     */
+    uint32_t axes_length;
+
+    /**
+     * Normalized values for the axes, indices valid up to |axesLength|-1. Axis
+     * values range from -1..1, and are in order of "importance".
+     */
+    float_t[16] axes;
+
+    /**
+     * Number of valid elements in the |buttons| array.
+     */
+    uint32_t buttons_length;
+
+    /**
+     * Normalized values for the buttons, indices valid up to |buttonsLength|
+     * - 1. Button values range from 0..1, and are in order of importance.
+     */
+    float_t[32] buttons;
+};
+
+/**
+ * The data for all gamepads connected to the system.
+ */
+struct PP_GamepadsData_Dev {
+    /**
+     * Number of valid elements in the |items| array.
+     */
+    uint32_t length;
+
+    /**
+     * Data for an individual gamepad device connected to the system.
+     */
+    PP_GamepadData_Dev[4] items;
+};
+
+/**
+ * The <code>PPB_Gamepad_Dev</code> interface allows retrieving data from
+ * gamepad/joystick devices that are connected to the system.
+ */
+[version=0.1, macro="PPB_GAMEPAD_DEV_INTERFACE"]
+interface PPB_Gamepad_Dev {
+  /**
+   * Samples the current state of the connected gamepads.
+   */
+  void SampleGamepads(
+      [in] PP_Instance instance,
+      [out] PP_GamepadsData_Dev data);
+
+};
diff --git a/ppapi/c/dev/ppb_gamepad_dev.h b/ppapi/c/dev/ppb_gamepad_dev.h
new file mode 100644
index 0000000..63197bc
--- /dev/null
+++ b/ppapi/c/dev/ppb_gamepad_dev.h
@@ -0,0 +1,106 @@
+/* Copyright (c) 2012 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.
+ */
+
+/* From dev/ppb_gamepad_dev.idl modified Mon Jan  9 13:16:43 2012. */
+
+#ifndef PPAPI_C_DEV_PPB_GAMEPAD_DEV_H_
+#define PPAPI_C_DEV_PPB_GAMEPAD_DEV_H_
+
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/c/pp_macros.h"
+#include "ppapi/c/pp_stdint.h"
+
+#define PPB_GAMEPAD_DEV_INTERFACE_0_1 "PPB_Gamepad(Dev);0.1"
+#define PPB_GAMEPAD_DEV_INTERFACE PPB_GAMEPAD_DEV_INTERFACE_0_1
+
+/**
+ * @file
+ * This file defines the <code>PPB_Gamepad_Dev</code> interface, which
+ * provides access to gamepad devices.
+ */
+
+
+/**
+ * @addtogroup Structs
+ * @{
+ */
+/**
+ * The data for one gamepad device.
+ */
+struct PP_GamepadData_Dev {
+  /**
+   * Is there a gamepad connected at this index? If this is false, no other
+   * data in this structure is valid.
+   */
+  char connected;
+  /**
+   * String identifier for the type of device/manufacturer.
+   */
+  uint16_t id[128];
+  /**
+   * Monotonically increasing value that is incremented when the data have
+   * been updated.
+   */
+  uint64_t timestamp;
+  /**
+   * Number of valid elements in the |axes| array.
+   */
+  uint32_t axes_length;
+  /**
+   * Normalized values for the axes, indices valid up to |axesLength|-1. Axis
+   * values range from -1..1, and are in order of "importance".
+   */
+  float axes[16];
+  /**
+   * Number of valid elements in the |buttons| array.
+   */
+  uint32_t buttons_length;
+  /**
+   * Normalized values for the buttons, indices valid up to |buttonsLength|
+   * - 1. Button values range from 0..1, and are in order of importance.
+   */
+  float buttons[32];
+};
+
+/**
+ * The data for all gamepads connected to the system.
+ */
+struct PP_GamepadsData_Dev {
+  /**
+   * Number of valid elements in the |items| array.
+   */
+  uint32_t length;
+  /**
+   * Data for an individual gamepad device connected to the system.
+   */
+  struct PP_GamepadData_Dev items[4];
+};
+/**
+ * @}
+ */
+
+/**
+ * @addtogroup Interfaces
+ * @{
+ */
+/**
+ * The <code>PPB_Gamepad_Dev</code> interface allows retrieving data from
+ * gamepad/joystick devices that are connected to the system.
+ */
+struct PPB_Gamepad_Dev_0_1 {
+  /**
+   * Samples the current state of the connected gamepads.
+   */
+  void (*SampleGamepads)(PP_Instance instance,
+                         struct PP_GamepadsData_Dev* data);
+};
+
+typedef struct PPB_Gamepad_Dev_0_1 PPB_Gamepad_Dev;
+/**
+ * @}
+ */
+
+#endif  /* PPAPI_C_DEV_PPB_GAMEPAD_DEV_H_ */
+
diff --git a/ppapi/examples/gamepad/gamepad.cc b/ppapi/examples/gamepad/gamepad.cc
new file mode 100644
index 0000000..60ef589
--- /dev/null
+++ b/ppapi/examples/gamepad/gamepad.cc
@@ -0,0 +1,151 @@
+// Copyright (c) 2012 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 <cmath>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "ppapi/c/dev/ppb_console_dev.h"
+#include "ppapi/c/dev/ppb_gamepad_dev.h"
+#include "ppapi/c/ppb_input_event.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/graphics_2d.h"
+#include "ppapi/cpp/image_data.h"
+#include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/logging.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/rect.h"
+#include "ppapi/cpp/var.h"
+#include "ppapi/cpp/view.h"
+#include "ppapi/utility/completion_callback_factory.h"
+
+void FillRect(pp::ImageData* image, int left, int top, int width, int height,
+              uint32_t color) {
+  for (int y = std::max(0, top);
+       y < std::min(image->size().height() - 1, top + height);
+       y++) {
+    for (int x = std::max(0, left);
+         x < std::min(image->size().width() - 1, left + width);
+         x++)
+      *image->GetAddr32(pp::Point(x, y)) = color;
+  }
+}
+
+class MyInstance : public pp::Instance {
+ public:
+  explicit MyInstance(PP_Instance instance)
+      : pp::Instance(instance),
+        width_(0),
+        height_(0),
+        callback_factory_(this),
+        gamepad_(NULL) {
+  }
+  virtual ~MyInstance() {}
+
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    gamepad_ = reinterpret_cast<const PPB_Gamepad_Dev*>(
+        pp::Module::Get()->GetBrowserInterface(PPB_GAMEPAD_DEV_INTERFACE));
+    if (!gamepad_)
+      return false;
+
+    RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE |
+                       PP_INPUTEVENT_CLASS_KEYBOARD);
+    return true;
+  }
+
+  virtual void DidChangeView(const pp::View& view) {
+    pp::Rect rect = view.GetRect();
+    if (rect.size().width() == width_ &&
+        rect.size().height() == height_)
+      return;  // We don't care about the position, only the size.
+
+    width_ = rect.size().width();
+    height_ = rect.size().height();
+
+    device_context_ = pp::Graphics2D(this, pp::Size(width_, height_), false);
+    if (!BindGraphics(device_context_))
+      return;
+
+    Paint();
+  }
+
+  void OnFlush(int32_t) {
+    Paint();
+  }
+
+ private:
+  void Paint() {
+    pp::ImageData image = PaintImage(device_context_.size());
+    if (!image.is_null()) {
+      device_context_.ReplaceContents(&image);
+      device_context_.Flush(
+          callback_factory_.NewRequiredCallback(&MyInstance::OnFlush));
+    } else {
+      printf("NullImage\n");
+    }
+  }
+
+  pp::ImageData PaintImage(const pp::Size& size) {
+    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL, size, false);
+    if (image.is_null())
+      return image;
+
+    PP_GamepadsData_Dev gamepad_data;
+    gamepad_->SampleGamepads(pp_instance(), &gamepad_data);
+
+    int width2 = size.width() / 2;
+    int height2 = size.height() / 2;
+    // Draw 2 axes
+    for (size_t i = 0; i < gamepad_data.items[0].axes_length; i += 2) {
+      int x = static_cast<int>(
+          gamepad_data.items[0].axes[i + 0] * width2 + width2);
+      int y = static_cast<int>(
+          gamepad_data.items[0].axes[i + 1] * height2 + height2);
+      uint32_t box_bgra = 0x80000000;  // Alpha 50%.
+      FillRect(&image, x - 3, y - 3, 7, 7, box_bgra);
+    }
+
+    for (size_t i = 0; i < gamepad_data.items[0].buttons_length; ++i) {
+      float button_val = gamepad_data.items[0].buttons[i];
+      uint32_t colour = static_cast<uint32_t>((button_val * 192) + 63) << 24;
+      int x = i * 8 + 10;
+      int y = 10;
+      FillRect(&image, x - 3, y - 3, 7, 7, colour);
+    }
+    return image;
+  }
+
+  int width_;
+  int height_;
+
+  pp::CompletionCallbackFactory<MyInstance> callback_factory_;
+
+  const PPB_Gamepad_Dev* gamepad_;
+
+  pp::Graphics2D device_context_;
+};
+
+// This object is the global object representing this plugin library as long
+// as it is loaded.
+class MyModule : public pp::Module {
+ public:
+  MyModule() : pp::Module() {}
+  virtual ~MyModule() {}
+
+  // Override CreateInstance to create your customized Instance object.
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new MyInstance(instance);
+  }
+};
+
+namespace pp {
+
+// Factory function for your specialization of the Module object.
+Module* CreateModule() {
+  return new MyModule();
+}
+
+}  // namespace pp
+
diff --git a/ppapi/examples/gamepad/gamepad.html b/ppapi/examples/gamepad/gamepad.html
new file mode 100644
index 0000000..6e400dd
--- /dev/null
+++ b/ppapi/examples/gamepad/gamepad.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+  <!--
+  Copyright (c) 2012 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.
+  -->
+<head>
+  <title>Gamepad Example</title>
+</head>
+<body>
+<div>
+  <object id="plugin" type="application/x-ppapi-example-gamepad"
+      width="300" height="300" border="2px"></object>
+</div>
+</body>
+</html>
diff --git a/ppapi/ppapi_shared.gypi b/ppapi/ppapi_shared.gypi
index 0cafb51..2802b5d 100644
--- a/ppapi/ppapi_shared.gypi
+++ b/ppapi/ppapi_shared.gypi
@@ -158,6 +158,7 @@
         'thunk/ppb_font_api.h',
         'thunk/ppb_font_thunk.cc',
         'thunk/ppb_fullscreen_thunk.cc',
+        'thunk/ppb_gamepad_thunk.cc',
         'thunk/ppb_gles_chromium_texture_mapping_thunk.cc',
         'thunk/ppb_graphics_2d_api.h',
         'thunk/ppb_graphics_2d_thunk.cc',
diff --git a/ppapi/ppapi_sources.gypi b/ppapi/ppapi_sources.gypi
index f517a12..a2c6884 100644
--- a/ppapi/ppapi_sources.gypi
+++ b/ppapi/ppapi_sources.gypi
@@ -61,6 +61,7 @@
       'c/dev/ppb_find_dev.h',
       'c/dev/ppb_font_dev.h',
       'c/dev/ppb_fullscreen_dev.h',
+      'c/dev/ppb_gamepad_dev.h',
       'c/dev/ppb_ime_input_event_dev.h',
       'c/dev/ppb_memory_dev.h',
       'c/dev/ppb_resource_array_dev.h',
diff --git a/ppapi/ppapi_tests.gypi b/ppapi/ppapi_tests.gypi
index 26d2527..0e23631 100644
--- a/ppapi/ppapi_tests.gypi
+++ b/ppapi/ppapi_tests.gypi
@@ -1,4 +1,4 @@
-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Copyright (c) 2012 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.
 
@@ -200,6 +200,17 @@
     },
 
     {
+      'target_name': 'ppapi_example_gamepad',
+      'dependencies': [
+        'ppapi_example_skeleton',
+        'ppapi.gyp:ppapi_cpp',
+      ],
+      'sources': [
+        'examples/gamepad/gamepad.cc',
+      ],
+    },
+
+    {
       'target_name': 'ppapi_example_c_stub',
       'dependencies': [
         'ppapi_example_skeleton',
diff --git a/ppapi/proxy/ppb_instance_proxy.cc b/ppapi/proxy/ppb_instance_proxy.cc
index f8dd8a2..1a71966 100644
--- a/ppapi/proxy/ppb_instance_proxy.cc
+++ b/ppapi/proxy/ppb_instance_proxy.cc
@@ -267,6 +267,11 @@ PP_Bool PPB_Instance_Proxy::FlashGetScreenSize(PP_Instance instance,
   return result;
 }
 
+void PPB_Instance_Proxy::SampleGamepads(PP_Instance instance,
+                                        PP_GamepadsData_Dev* data) {
+  NOTIMPLEMENTED();
+}
+
 int32_t PPB_Instance_Proxy::RequestInputEvents(PP_Instance instance,
                                                uint32_t event_classes) {
   dispatcher()->Send(new PpapiHostMsg_PPBInstance_RequestInputEvents(
diff --git a/ppapi/proxy/ppb_instance_proxy.h b/ppapi/proxy/ppb_instance_proxy.h
index a88bd6f..0ce2562 100644
--- a/ppapi/proxy/ppb_instance_proxy.h
+++ b/ppapi/proxy/ppb_instance_proxy.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -75,6 +75,8 @@ class PPB_Instance_Proxy : public InterfaceProxy,
                                     PP_Bool fullscreen) OVERRIDE;
   virtual PP_Bool FlashGetScreenSize(PP_Instance instance, PP_Size* size)
       OVERRIDE;
+  virtual void SampleGamepads(PP_Instance instance, PP_GamepadsData_Dev* data)
+      OVERRIDE;
   virtual int32_t RequestInputEvents(PP_Instance instance,
                                      uint32_t event_classes) OVERRIDE;
   virtual int32_t RequestFilteringInputEvents(PP_Instance instance,
diff --git a/ppapi/tests/all_c_includes.h b/ppapi/tests/all_c_includes.h
index 10b66d3..6189968 100644
--- a/ppapi/tests/all_c_includes.h
+++ b/ppapi/tests/all_c_includes.h
@@ -21,6 +21,7 @@
 #include "ppapi/c/dev/ppb_find_dev.h"
 #include "ppapi/c/dev/ppb_font_dev.h"
 #include "ppapi/c/dev/ppb_fullscreen_dev.h"
+#include "ppapi/c/dev/ppb_gamepad_dev.h"
 #include "ppapi/c/dev/ppb_ime_input_event_dev.h"
 #include "ppapi/c/dev/ppb_layer_compositor_dev.h"
 #include "ppapi/c/dev/ppb_memory_dev.h"
diff --git a/ppapi/thunk/interfaces_ppb_public_dev.h b/ppapi/thunk/interfaces_ppb_public_dev.h
index f72fa7c..de3b62b 100644
--- a/ppapi/thunk/interfaces_ppb_public_dev.h
+++ b/ppapi/thunk/interfaces_ppb_public_dev.h
@@ -43,6 +43,7 @@ PROXIED_IFACE(PPB_FileChooser, PPB_FILECHOOSER_DEV_INTERFACE_0_5,
 PROXIED_IFACE(PPB_Font, PPB_FONT_DEV_INTERFACE_0_6, PPB_Font_Dev_0_6)
 PROXIED_IFACE(PPB_Instance, PPB_CHAR_SET_DEV_INTERFACE_0_4, PPB_CharSet_Dev_0_4)
 PROXIED_IFACE(PPB_Instance, PPB_CONSOLE_DEV_INTERFACE_0_1, PPB_Console_Dev_0_1)
+PROXIED_IFACE(PPB_Instance, PPB_GAMEPAD_DEV_INTERFACE_0_1, PPB_Gamepad_Dev_0_1)
 PROXIED_IFACE(PPB_Instance, PPB_URLUTIL_DEV_INTERFACE_0_6, PPB_URLUtil_Dev_0_6)
 UNPROXIED_IFACE(PPB_Instance, PPB_ZOOM_DEV_INTERFACE_0_2, PPB_Zoom_Dev_0_2)
 UNPROXIED_IFACE(PPB_LayerCompositor, PPB_LAYER_COMPOSITOR_DEV_INTERFACE_0_2,
diff --git a/ppapi/thunk/ppb_gamepad_thunk.cc b/ppapi/thunk/ppb_gamepad_thunk.cc
new file mode 100644
index 0000000..9bf2122
--- /dev/null
+++ b/ppapi/thunk/ppb_gamepad_thunk.cc
@@ -0,0 +1,34 @@
+// Copyright (c) 2012 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 "ppapi/c/dev/ppb_gamepad_dev.h"
+#include "ppapi/thunk/thunk.h"
+#include "ppapi/thunk/enter.h"
+#include "ppapi/thunk/ppb_instance_api.h"
+#include "ppapi/thunk/resource_creation_api.h"
+
+namespace ppapi {
+namespace thunk {
+
+namespace {
+
+void SampleGamepads(PP_Instance instance, PP_GamepadsData_Dev* data) {
+  EnterFunction<PPB_Instance_FunctionAPI> enter(instance, true);
+  if (enter.failed())
+    return;
+  enter.functions()->SampleGamepads(instance, data);
+}
+
+const PPB_Gamepad_Dev g_ppb_gamepad_thunk = {
+  &SampleGamepads,
+};
+
+}  // namespace
+
+const PPB_Gamepad_Dev* GetPPB_Gamepad_Dev_0_1_Thunk() {
+  return &g_ppb_gamepad_thunk;
+}
+
+}  // namespace thunk
+}  // namespace ppapi
diff --git a/ppapi/thunk/ppb_instance_api.h b/ppapi/thunk/ppb_instance_api.h
index 8151479..013f61b 100644
--- a/ppapi/thunk/ppb_instance_api.h
+++ b/ppapi/thunk/ppb_instance_api.h
@@ -1,10 +1,11 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
 #ifndef PPAPI_THUNK_INSTANCE_API_H_
 #define PPAPI_THUNK_INSTANCE_API_H_
 
+#include "ppapi/c/dev/ppb_gamepad_dev.h"
 #include "ppapi/c/dev/ppb_url_util_dev.h"
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/ppb_instance.h"
@@ -71,6 +72,10 @@ class PPB_Instance_FunctionAPI {
                                      PP_Bool fullscreen) = 0;
   virtual PP_Bool FlashGetScreenSize(PP_Instance instance, PP_Size* size) = 0;
 
+  // Gamepad.
+  virtual void SampleGamepads(PP_Instance instance,
+                              PP_GamepadsData_Dev* data) = 0;
+
   // InputEvent.
   virtual int32_t RequestInputEvents(PP_Instance instance,
                                      uint32_t event_classes) = 0;
diff --git a/webkit/plugins/ppapi/mock_plugin_delegate.cc b/webkit/plugins/ppapi/mock_plugin_delegate.cc
index a991c50..da371c54 100644
--- a/webkit/plugins/ppapi/mock_plugin_delegate.cc
+++ b/webkit/plugins/ppapi/mock_plugin_delegate.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -8,6 +8,7 @@
 #include "base/message_loop_proxy.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/shared_impl/ppapi_preferences.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebGamepads.h"
 #include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
 
 namespace webkit {
@@ -361,6 +362,10 @@ void MockPluginDelegate::DidChangeCursor(PluginInstance* instance,
 void MockPluginDelegate::DidReceiveMouseEvent(PluginInstance* instance) {
 }
 
+void MockPluginDelegate::SampleGamepads(WebKit::WebGamepads* data) {
+  data->length = 0;
+}
+
 bool MockPluginDelegate::IsInFullscreenMode() {
   return false;
 }
diff --git a/webkit/plugins/ppapi/mock_plugin_delegate.h b/webkit/plugins/ppapi/mock_plugin_delegate.h
index 7fe0155..fbd961a 100644
--- a/webkit/plugins/ppapi/mock_plugin_delegate.h
+++ b/webkit/plugins/ppapi/mock_plugin_delegate.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -153,6 +153,7 @@ class MockPluginDelegate : public PluginDelegate {
   virtual void DidChangeCursor(PluginInstance* instance,
                                const WebKit::WebCursorInfo& cursor);
   virtual void DidReceiveMouseEvent(PluginInstance* instance);
+  virtual void SampleGamepads(WebKit::WebGamepads* data) OVERRIDE;
   virtual bool IsInFullscreenMode();
   virtual bool IsPageVisible() const;
 };
diff --git a/webkit/plugins/ppapi/plugin_delegate.h b/webkit/plugins/ppapi/plugin_delegate.h
index af93ec8..6f9a17e 100644
--- a/webkit/plugins/ppapi/plugin_delegate.h
+++ b/webkit/plugins/ppapi/plugin_delegate.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -59,6 +59,7 @@ class PlatformCanvas;
 
 namespace WebKit {
 class WebFileChooserCompletion;
+class WebGamepads;
 struct WebCursorInfo;
 struct WebFileChooserParams;
 }
@@ -515,6 +516,9 @@ class PluginDelegate {
   // Determines if the browser entered fullscreen mode.
   virtual bool IsInFullscreenMode() = 0;
 
+  // Retrieve current gamepad data.
+  virtual void SampleGamepads(WebKit::WebGamepads* data) = 0;
+
   // Returns true if the containing page is visible.
   virtual bool IsPageVisible() const = 0;
 };
diff --git a/webkit/plugins/ppapi/ppapi_plugin_instance.cc b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
index 63536bc..b3782d3 100644
--- a/webkit/plugins/ppapi/ppapi_plugin_instance.cc
+++ b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
@@ -14,6 +14,7 @@
 #include "base/utf_string_conversions.h"
 #include "ppapi/c/dev/ppb_console_dev.h"
 #include "ppapi/c/dev/ppb_find_dev.h"
+#include "ppapi/c/dev/ppb_gamepad_dev.h"
 #include "ppapi/c/dev/ppb_zoom_dev.h"
 #include "ppapi/c/dev/ppp_find_dev.h"
 #include "ppapi/c/dev/ppp_selection_dev.h"
@@ -45,6 +46,7 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDocument.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebElement.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebGamepads.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPluginContainer.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSecurityOrigin.h"
@@ -226,6 +228,13 @@ COMPILE_ASSERT_MATCHING_ENUM(TypeGrabbing, PP_CURSORTYPE_GRABBING);
 // Do not assert WebCursorInfo::TypeCustom == PP_CURSORTYPE_CUSTOM;
 // PP_CURSORTYPE_CUSTOM is pinned to allow new cursor types.
 
+// Ensure conversion from WebKit::WebGamepads to PP_GamepadsData_Dev is safe.
+// See also DCHECKs in SampleGamepads below.
+COMPILE_ASSERT(sizeof(WebKit::WebGamepads) == sizeof(PP_GamepadsData_Dev),
+               size_difference);
+COMPILE_ASSERT(sizeof(WebKit::WebGamepad) == sizeof(PP_GamepadData_Dev),
+               size_difference);
+
 // Sets |*security_origin| to be the WebKit security origin associated with the
 // document containing the given plugin instance. On success, returns true. If
 // the instance is invalid, returns false and |*security_origin| will be
@@ -1310,6 +1319,42 @@ int32_t PluginInstance::Navigate(PPB_URLRequestInfo_Impl* request,
   return PP_OK;
 }
 
+void PluginInstance::SampleGamepads(PP_Instance instance,
+                                    PP_GamepadsData_Dev* data) {
+
+  // Because the WebKit objects have trivial ctors, using offsetof doesn't
+  // work. Instead use this version based on src/v8/src/globals.h. This
+  // workaround doesn't work in constant expressions as required for
+  // COMPILE_ASSERT, so DCHECK instead.
+
+#define OFFSET_OF(type, field) \
+  (reinterpret_cast<intptr_t>(&(reinterpret_cast<type*>(4)->field)) - 4)
+
+#define DCHECK_GAMEPADS_OFFSET(webkit_name, pp_name) \
+  DCHECK(OFFSET_OF(WebKit::WebGamepads, webkit_name) \
+             == OFFSET_OF(PP_GamepadsData_Dev, pp_name))
+
+#define DCHECK_GAMEPAD_OFFSET(webkit_name, pp_name) \
+  DCHECK(OFFSET_OF(WebKit::WebGamepad, webkit_name) \
+             == OFFSET_OF(PP_GamepadData_Dev, pp_name))
+
+  DCHECK_GAMEPADS_OFFSET(length, length);
+  DCHECK_GAMEPADS_OFFSET(items, items);
+  DCHECK_GAMEPAD_OFFSET(connected, connected);
+  DCHECK_GAMEPAD_OFFSET(id, id);
+  DCHECK_GAMEPAD_OFFSET(timestamp, timestamp);
+  DCHECK_GAMEPAD_OFFSET(axesLength, axes_length);
+  DCHECK_GAMEPAD_OFFSET(axes, axes);
+  DCHECK_GAMEPAD_OFFSET(buttonsLength, buttons_length);
+  DCHECK_GAMEPAD_OFFSET(buttons, buttons);
+
+#undef OFFSET_OF
+#undef DCHECK_GAMEPADS_OFFSET
+#undef DCHECK_GAMEPAD_OFFSET
+
+  delegate()->SampleGamepads(reinterpret_cast<WebKit::WebGamepads*>(data));
+}
+
 bool PluginInstance::IsViewAccelerated() {
   if (!container_)
     return false;
diff --git a/webkit/plugins/ppapi/ppapi_plugin_instance.h b/webkit/plugins/ppapi/ppapi_plugin_instance.h
index cbafec1..3caef5c 100644
--- a/webkit/plugins/ppapi/ppapi_plugin_instance.h
+++ b/webkit/plugins/ppapi/ppapi_plugin_instance.h
@@ -16,6 +16,7 @@
 #include "base/string16.h"
 #include "googleurl/src/gurl.h"
 #include "ppapi/c/dev/pp_cursor_type_dev.h"
+#include "ppapi/c/dev/ppb_gamepad_dev.h"
 #include "ppapi/c/dev/ppp_printing_dev.h"
 #include "ppapi/c/dev/ppp_find_dev.h"
 #include "ppapi/c/dev/ppp_selection_dev.h"
@@ -287,6 +288,10 @@ class WEBKIT_PLUGINS_EXPORT PluginInstance :
                    const char* target,
                    bool from_user_action);
 
+  // Implementation of PPB_Gamepad.
+  void SampleGamepads(PP_Instance instance, PP_GamepadsData_Dev* data)
+      OVERRIDE;
+
   // Implementation of PPP_Messaging.
   void HandleMessage(PP_Var message);