Log device/usb messages to chrome://device-log.

device/usb/usb_device_impl.cc

Index: device/usb/usb_device_impl.cc
diff --git a/device/usb/usb_device_impl.cc b/device/usb/usb_device_impl.cc
index 782b0caa182a01c94c6601c5e59c36fc3fd21e29..8695fef3f3fea66eef2ad4efe2c994bd5331c236 100644
--- a/device/usb/usb_device_impl.cc
+++ b/device/usb/usb_device_impl.cc
@@ -17,6 +17,7 @@
 #include "device/usb/usb_descriptors.h"
 #include "device/usb/usb_device_handle_impl.h"
 #include "device/usb/usb_error.h"
+#include "device/usb/usb_log.h"
 #include "third_party/libusb/src/libusb/libusb.h"
 
 #if defined(OS_CHROMEOS)
@@ -221,7 +222,8 @@ scoped_refptr<UsbDeviceHandle> UsbDeviceImpl::Open() {
     handles_.push_back(device_handle);
     return device_handle;
   } else {
-    VLOG(1) << "Failed to open device: " << ConvertPlatformUsbErrorToString(rv);
+    USB_LOG(DEBUG) << "Failed to open device: "
+                   << ConvertPlatformUsbErrorToString(rv);

[stevenjb, 2015/02/20 00:01:27]

These seem like they should be actual ERROR events.

     return NULL;
   }
 }
@@ -302,8 +304,8 @@ void UsbDeviceImpl::RefreshConfiguration() {
   int rv =
       libusb_get_active_config_descriptor(platform_device_, &platform_config);
   if (rv != LIBUSB_SUCCESS) {
-    VLOG(1) << "Failed to get config descriptor: "
-            << ConvertPlatformUsbErrorToString(rv);
+    USB_LOG(DEBUG) << "Failed to get config descriptor: "
+                   << ConvertPlatformUsbErrorToString(rv);
     return;
   }
 
@@ -382,11 +384,12 @@ void UsbDeviceImpl::CacheStrings() {
       }
       device_handle->Close();
     } else {
-      VLOG(1) << "Failed to open device to cache string descriptors.";
+      USB_LOG(DEBUG) << "Failed to open device to cache string descriptors.";
     }
   } else {
-    VLOG(1) << "Failed to read device descriptor to cache string descriptors: "
-            << ConvertPlatformUsbErrorToString(rv);
+    USB_LOG(DEBUG)
+        << "Failed to read device descriptor to cache string descriptors: "
+        << ConvertPlatformUsbErrorToString(rv);
   }
   strings_cached_ = true;
 }