Fixed crash when exiting page using GVR controller w/ the gamepad API

device/vr/android/gvr/gvr_gamepad_data_fetcher.cc

 // Copyright 2016 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 "device/vr/android/gvr/gvr_gamepad_data_fetcher.h"
 
 #include "base/strings/utf_string_conversions.h"
 
 #include "device/vr/android/gvr/gvr_delegate.h"
 #include "third_party/WebKit/public/platform/WebGamepads.h"
@@ skipping 39 matching lines @@
                                              unsigned int display_id)
     : display_id_(display_id) {
   gvr::GvrApi* gvr_api = delegate->gvr_api();
   controller_api_.reset(new gvr::ControllerApi());
   int32_t options = gvr::ControllerApi::DefaultOptions();
   options |= GVR_CONTROLLER_ENABLE_GYRO;
   bool success = controller_api_->Init(options, gvr_api->GetContext());
   if (!success)
     controller_api_.reset(nullptr);
 
-  user_prefs_.reset(new gvr::UserPrefs(gvr_api->GetUserPrefs().cobj()));

[billorr, 2016/11/18 22:27:52]

I assume the bug is that the user_prefs_ object goes away at the wrong time.  So
the fix is just extracting data while we know the user_prefs is good?

Is controller_api_ still valid?

+  // TODO(bajones): Monitor changes to the controller handedness.
+  handedness_ = gvr_api->GetUserPrefs().GetControllerHandedness();
 }
 
 GvrGamepadDataFetcher::~GvrGamepadDataFetcher() {}
 
 GamepadSource GvrGamepadDataFetcher::source() {
   return GAMEPAD_SOURCE_GVR;
 }
 
 void GvrGamepadDataFetcher::OnAddedToProvider() {
   PauseHint(false);
@@ skipping 13 matching lines @@
     // initialization
     pad.connected = true;
     CopyToWebUString(pad.id, WebGamepad::idLengthCap,
                      base::UTF8ToUTF16("Daydream Controller"));
     CopyToWebUString(pad.mapping, WebGamepad::mappingLengthCap,
                      base::UTF8ToUTF16(""));
     pad.buttonsLength = 1;
     pad.axesLength = 2;
 
     pad.displayId = display_id_;
+
+    pad.hand = (handedness_ == GVR_CONTROLLER_RIGHT_HANDED) ? GamepadHandRight
+                                                            : GamepadHandLeft;
   }
 
   controller_state_.Update(*controller_api_);
 
   pad.timestamp = controller_state_.GetLastOrientationTimestamp();
 
-  // TODO: Query from API if avaialable.
-  gvr::ControllerHandedness handedness = user_prefs_->GetControllerHandedness();
-  pad.hand = (handedness == GVR_CONTROLLER_RIGHT_HANDED) ? GamepadHandRight
-                                                         : GamepadHandLeft;
-
   if (controller_state_.IsTouching()) {
     gvr_vec2f touch_position = controller_state_.GetTouchPos();
     pad.axes[0] = (touch_position.x * 2.0f) - 1.0f;
     pad.axes[1] = (touch_position.y * 2.0f) - 1.0f;
   } else {
     pad.axes[0] = 0.0f;
     pad.axes[1] = 0.0f;
   }
 
   pad.buttons[0].touched = controller_state_.IsTouching();
@@ skipping 30 matching lines @@
     return;
 
   if (paused) {
     controller_api_->Pause();
   } else {
     controller_api_->Resume();
   }
 }
 
 }  // namespace device