Fixes crashing in RequestUsbDevicesAccess

Pointer returned by vector::begin is not checked before use.

BUG=291012, 288070

Review URL: https://chromiumcodereview.appspot.com/23475048

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223516 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/api/usb/usb_api.cc

@@ -325,6 +325,10 @@ void RequestUsbDevicesAccess(
     ScopedDeviceVector devices,
     int interface_id,
     const base::Callback<void(ScopedDeviceVector result)>& callback) {
+  if (devices->empty()) {
+    callback.Run(devices.Pass());
+    return;
+  }
   (*devices->begin())->RequestUsbAcess(
       interface_id,
       base::Bind(RequestUsbDevicesAccessHelper, base::Passed(devices.Pass()),

chrome/browser/usb/usb_device.cc

@@ -20,6 +20,17 @@
 
 using content::BrowserThread;
 
+namespace {
+
+void OnRequestUsbAccessReplied(
+    const base::Callback<void(bool success)>& callback,
+    bool success) {
+  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
+                          base::Bind(callback, success));
+}
+
+}  // namespace
+
 UsbDevice::UsbDevice(
     scoped_refptr<UsbContext> context,
     PlatformUsbDevice platform_device,
@@ -55,6 +66,7 @@ UsbDevice::~UsbDevice() {
 }
 
 #if defined(OS_CHROMEOS)
+
 void UsbDevice::RequestUsbAcess(
     int interface_id,
     const base::Callback<void(bool success)>& callback) {
@@ -78,19 +90,10 @@ void UsbDevice::RequestUsbAcess(
                    this->vendor_id_,
                    this->product_id_,
                    interface_id,
-                   base::Bind(&UsbDevice::OnRequestUsbAccessReplied,
-                              base::Unretained(this),
-                              callback)));
+                   base::Bind(&OnRequestUsbAccessReplied, callback)));
   }
 }
 
-void UsbDevice::OnRequestUsbAccessReplied(
-    const base::Callback<void(bool success)>& callback,
-    bool success) {
-  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-                          base::Bind(callback, success));
-}
-
 #endif
 
 scoped_refptr<UsbDeviceHandle> UsbDevice::Open() {

chrome/browser/usb/usb_device.h

@@ -73,15 +73,6 @@ class UsbDevice : public base::RefCountedThreadSafe<UsbDevice> {
   // Called only be UsbService.
   virtual void OnDisconnect();
 
-#if defined(OS_CHROMEOS)
-  // This method is called when permission broker replied our request.
-  // We will simply relay it to FILE thread.
-  // |callback| comes first because it will be base::Bind'ed.
-  void OnRequestUsbAccessReplied(
-      const base::Callback<void(bool success)>& callback,
-      bool success);
-#endif  // OS_CHROMEOS
-
  private:
   PlatformUsbDevice platform_device_;
   uint16 vendor_id_;