Fix some thread safety violations in device::GvrDelegate implementation.

chrome/browser/android/vr_shell/vr_shell_gl.h

Index: chrome/browser/android/vr_shell/vr_shell_gl.h
diff --git a/chrome/browser/android/vr_shell/vr_shell_gl.h b/chrome/browser/android/vr_shell/vr_shell_gl.h
index 2720dd898fd00e73b1d5a08eaa73f30fec677ebd..85e25a14a9de6caf875ea822c44216b92ae0d404 100644
--- a/chrome/browser/android/vr_shell/vr_shell_gl.h
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.h
@@ -75,7 +75,6 @@ class VrShellGl {
                                 const gvr::Rectf& right_bounds);
   gvr::GvrApi* gvr_api();
   void SetGvrPoseForWebVr(const gvr::Mat4f& pose, uint32_t pose_num);
-  void SetWebVRRenderSurfaceSize(int width, int height);
   gvr::Sizei GetWebVRCompositorSurfaceSize();
 
   UiScene* GetScene() { return scene_.get(); }
@@ -107,7 +106,7 @@ class VrShellGl {
                              const base::TimeDelta interval);
   void ScheduleNextDrawFrame();
 
-  void ForceExitVR();
+  void ForceExitVr();
 
   // samplerExternalOES texture data for UI content image.
   int ui_texture_id_ = 0;
@@ -137,12 +136,6 @@ class VrShellGl {
   gvr::Sizei render_size_primary_;
   gvr::Sizei render_size_headlocked_;
 
-  // Intended size for the primary render buffer by UI mode.
-  // For WebVR, a size of 0x0 is used to indicate "not yet ready"
-  // to suppress rendering while still initializing.
-  gvr::Sizei render_size_primary_webvr_ = device::kInvalidRenderTargetSize;
-  gvr::Sizei render_size_primary_vrshell_;
-
   std::unique_ptr<VrShellRenderer> vr_shell_renderer_;
 
   bool touch_pending_ = false;