Revert of Refactoring gamepad polling to support dynamically added sources

content/browser/gamepad/gamepad_data_fetcher.cc

 // Copyright (c) 2015 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 "content/browser/gamepad/gamepad_data_fetcher.h"
 
+#include <stddef.h>
+#include <string.h>
+
+#include "base/logging.h"
+#include "build/build_config.h"
+
+namespace {
+
+#if !defined(OS_ANDROID)
+const float kMinAxisResetValue = 0.1f;
+#endif
+
+}  // namespace
+
 namespace content {
 
-GamepadDataFetcher::GamepadDataFetcher() : provider_(nullptr) {
+using blink::WebGamepad;
+using blink::WebGamepads;
+
+#if !defined(OS_ANDROID)
+void GamepadDataFetcher::MapAndSanitizeGamepadData(
+    PadState* pad_state, WebGamepad* pad) {
+  DCHECK(pad_state);
+  DCHECK(pad);
+
+  if (!pad_state->data.connected) {
+    memset(pad, 0, sizeof(WebGamepad));
+    return;
+  }
+
+  // Copy the current state to the output buffer, using the mapping
+  // function, if there is one available.
+  if (pad_state->mapper)
+    pad_state->mapper(pad_state->data, pad);
+  else
+    *pad = pad_state->data;
+
+  // About sanitization: Gamepads may report input event if the user is not
+  // interacting with it, due to hardware problems or environmental ones (pad
+  // has something heavy leaning against an axis.) This may cause user gestures
+  // to be detected erroniously, exposing gamepad information when the user had
+  // no intention of doing so. To avoid this we require that each button or axis
+  // report being at rest (zero) at least once before exposing its value to the
+  // Gamepad API. This state is tracked by the axis_mask and button_mask
+  // bitfields. If the bit for an axis or button is 0 it means the axis has
+  // never reported being at rest, and the value will be forced to zero.
+
+  // We can skip axis sanitation if all available axes have been masked.
+  uint32_t full_axis_mask = (1 << pad->axesLength) - 1;
+  if (pad_state->axis_mask != full_axis_mask) {
+    for (size_t axis = 0; axis < pad->axesLength; ++axis) {
+      if (!(pad_state->axis_mask & 1 << axis)) {
+        if (fabs(pad->axes[axis]) < kMinAxisResetValue) {
+          pad_state->axis_mask |= 1 << axis;
+        } else {
+          pad->axes[axis] = 0.0f;
+        }
+      }
+    }
+  }
+
+  // We can skip button sanitation if all available buttons have been masked.
+  uint32_t full_button_mask = (1 << pad->buttonsLength) - 1;
+  if (pad_state->button_mask != full_button_mask) {
+    for (size_t button = 0; button < pad->buttonsLength; ++button) {
+      if (!(pad_state->button_mask & 1 << button)) {
+        if (!pad->buttons[button].pressed) {
+          pad_state->button_mask |= 1 << button;
+        } else {
+          pad->buttons[button].pressed = false;
+          pad->buttons[button].value = 0.0f;
+        }
+      }
+    }
+  }
 }
-
-void GamepadDataFetcher::InitializeProvider(GamepadProvider* provider) {
-  DCHECK(provider);
-
-  provider_ = provider;
-  OnAddedToProvider();
-}
+#endif
 
 }  // namespace content