hid: Remove size from receive APIs and return report ID separately.

The size parameter is unnecessary when calling chrome.hid.receive and
chrome.hid.receiveFeatureReport because, since the caller does not know
which report ID will be returned, it should always be set to the maximum
input or feature report size provided by the device. The size of the
report ID is now not included in the maximum report sizes for the device
since it no longer effects buffer size.

In addition increase consistency by always providing the report ID to
the chrome.hid.receive callback instead of including it as the first
byte of the data buffer only if it is non-zero.

BUG=

Review URL: https://codereview.chromium.org/413913003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@285989 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 9 insertions, 5 deletions

diff --git a/device/hid/hid_connection_mac.cc b/device/hid/hid_connection_mac.cc
index 521f287..d497ac0 100644
--- a/device/hid/hid_connection_mac.cc
+++ b/device/hid/hid_connection_mac.cc
@@ -17,10 +17,14 @@ HidConnectionMac::HidConnectionMac(HidDeviceInfo device_info)
   message_loop_ = base::MessageLoopProxy::current();
 
   DCHECK(device_.get());
-  inbound_buffer_.reset((uint8_t*)malloc(device_info.max_input_report_size));
+  size_t expected_report_size = device_info.max_input_report_size;
+  if (device_info.has_report_id) {
+    expected_report_size++;
+  }
+  inbound_buffer_.reset((uint8_t*)malloc(expected_report_size));
   IOHIDDeviceRegisterInputReportCallback(device_.get(),
                                          inbound_buffer_.get(),
-                                         device_info.max_input_report_size,
+                                         expected_report_size,
                                          &HidConnectionMac::InputReportCallback,
                                          this);
   IOHIDDeviceOpen(device_, kIOHIDOptionsTypeNone);
@@ -62,14 +66,14 @@ void HidConnectionMac::PlatformGetFeatureReport(
   }
 
   uint8_t* feature_report_buffer = reinterpret_cast<uint8_t*>(buffer->data());
-  CFIndex max_feature_report_size = device_info().max_feature_report_size;
+  CFIndex report_size = buffer->size();
   IOReturn result = IOHIDDeviceGetReport(device_,
                                          kIOHIDReportTypeFeature,
                                          report_id,
                                          feature_report_buffer,
-                                         &max_feature_report_size);
+                                         &report_size);
   if (result == kIOReturnSuccess)
-    callback.Run(true, max_feature_report_size);
+    callback.Run(true, report_size);
   else
     callback.Run(false, 0);
 }