Move device/usb classes from the FILE thread to UI thread.

device/usb/usb_device.h

Index: device/usb/usb_device.h
diff --git a/device/usb/usb_device.h b/device/usb/usb_device.h
index e82407805833ee13e8b1a352c8472f1c95e3e0f5..22864678b0eefaae23cec82caeb769c1a6842e2c 100644
--- a/device/usb/usb_device.h
+++ b/device/usb/usb_device.h
@@ -16,16 +16,24 @@ class UsbDeviceHandle;
 struct UsbConfigDescriptor;
 
 // A UsbDevice object represents a detected USB device, providing basic
-// information about it. For further manipulation of the device, a
-// UsbDeviceHandle must be created from Open() method.
+// information about it. Methods other than simple property accessors must be
+// called from the thread on which this object was created. For further
+// manipulation of the device, a UsbDeviceHandle must be created from Open()
+// method.
 class UsbDevice : public base::RefCountedThreadSafe<UsbDevice> {
  public:
-  typedef base::Callback<void(bool success)> ResultCallback;
+  using OpenCallback = base::Callback<void(scoped_refptr<UsbDeviceHandle>)>;
+  using ResultCallback = base::Callback<void(bool success)>;
 
   // Accessors to basic information.
   uint16 vendor_id() const { return vendor_id_; }
   uint16 product_id() const { return product_id_; }
   uint32 unique_id() const { return unique_id_; }
+  const base::string16& manufacturer_string() const {
+    return manufacturer_string_;
+  }
+  const base::string16& product_string() const { return product_string_; }
+  const base::string16& serial_number() const { return serial_number_; }
 
   // On ChromeOS the permission_broker service is used to change the ownership
   // of USB device nodes so that Chrome can open them. On other platforms these
@@ -37,37 +45,23 @@ class UsbDevice : public base::RefCountedThreadSafe<UsbDevice> {
                                 const ResultCallback& callback);
 
   // Creates a UsbDeviceHandle for further manipulation.
-  // Blocking method. Must be called on FILE thread.
-  virtual scoped_refptr<UsbDeviceHandle> Open() = 0;
+  virtual void Open(const OpenCallback& callback) = 0;
 
   // Explicitly closes a device handle. This method will be automatically called
   // by the destructor of a UsbDeviceHandle as well.
-  // Closing a closed handle is a safe
-  // Blocking method. Must be called on FILE thread.
   virtual bool Close(scoped_refptr<UsbDeviceHandle> handle) = 0;
 
   // Gets the UsbConfigDescriptor for the active device configuration or nullptr
   // if the device is unconfigured.
-  // Blocking method. Must be called on FILE thread.
   virtual const UsbConfigDescriptor* GetConfiguration() = 0;
 
-  // Gets the manufacturer string of the device, or false and an empty
-  // string. This is a blocking method and must be called on FILE thread.
-  // TODO(reillyg): Make this available from the UI thread. crbug.com/427985
-  virtual bool GetManufacturer(base::string16* manufacturer) = 0;
-
-  // Gets the product string of the device, or returns false and an empty
-  // string. This is a blocking method and must be called on FILE thread.
-  // TODO(reillyg): Make this available from the UI thread. crbug.com/427985
-  virtual bool GetProduct(base::string16* product) = 0;
-
-  // Gets the serial number string of the device, or returns false and an empty
-  // string. This is a blocking method and must be called on FILE thread.
-  // TODO(reillyg): Make this available from the UI thread. crbug.com/427985
-  virtual bool GetSerialNumber(base::string16* serial) = 0;
-
  protected:
-  UsbDevice(uint16 vendor_id, uint16 product_id, uint32 unique_id);
+  UsbDevice(uint16 vendor_id,
+            uint16 product_id,
+            uint32 unique_id,
+            const base::string16& manufacturer_string,
+            const base::string16& product_string,
+            const base::string16& serial_number);
   virtual ~UsbDevice();
 
  private:
@@ -76,6 +70,9 @@ class UsbDevice : public base::RefCountedThreadSafe<UsbDevice> {
   const uint16 vendor_id_;
   const uint16 product_id_;
   const uint32 unique_id_;
+  const base::string16 manufacturer_string_;
+  const base::string16 product_string_;
+  const base::string16 serial_number_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbDevice);
 };