Update device/usb and its Mojo interface for variable size ISO packets.

extensions/browser/api/usb/usb_api.cc

Index: extensions/browser/api/usb/usb_api.cc
diff --git a/extensions/browser/api/usb/usb_api.cc b/extensions/browser/api/usb/usb_api.cc
index 16710ddabbba41f9b003f5c6fed7d5b4cd442720..758dae02455a63a2563f798d68f05d182f9b211e 100644
--- a/extensions/browser/api/usb/usb_api.cc
+++ b/extensions/browser/api/usb/usb_api.cc
@@ -4,6 +4,8 @@
 
 #include "extensions/browser/api/usb/usb_api.h"
 
+#include <algorithm>
+#include <numeric>
 #include <string>
 #include <utility>
 #include <vector>
@@ -1134,48 +1136,88 @@ ExtensionFunction::ResponseAction UsbIsochronousTransferFunction::Run() {
   size_t size = 0;
   UsbEndpointDirection direction = device::USB_DIRECTION_INBOUND;
 
-  if (!ConvertDirectionFromApi(generic_transfer.direction, &direction)) {
+  if (!ConvertDirectionFromApi(generic_transfer.direction, &direction))
     return RespondNow(Error(kErrorConvertDirection));
-  }
 
-  if (!GetTransferSize(generic_transfer, &size)) {
+  if (!GetTransferSize(generic_transfer, &size))
     return RespondNow(Error(kErrorInvalidTransferLength));
-  }
 
-  if (transfer.packets < 0 || transfer.packets >= kMaxPackets) {
+  if (transfer.packets < 0 || transfer.packets >= kMaxPackets)
     return RespondNow(Error(kErrorInvalidNumberOfPackets));
-  }
+  size_t packets = transfer.packets;
 
-  unsigned int packets = transfer.packets;
   if (transfer.packet_length < 0 ||
       transfer.packet_length >= kMaxPacketLength) {
     return RespondNow(Error(kErrorInvalidPacketLength));
   }
 
-  unsigned int packet_length = transfer.packet_length;
-  const uint64_t total_length = packets * packet_length;
-  if (packets > size || total_length > size) {
+  size_t total_length = packets * transfer.packet_length;
+  if (packets > size || total_length > size)
     return RespondNow(Error(kErrorTransferLength));
-  }
-
-  scoped_refptr<net::IOBuffer> buffer =
-      CreateBufferForTransfer(generic_transfer, direction, size);
-  if (!buffer.get()) {
-    return RespondNow(Error(kErrorMalformedParameters));
-  }
+  std::vector<uint32_t> packet_lengths(packets, transfer.packet_length);
 
   int timeout = generic_transfer.timeout ? *generic_transfer.timeout : 0;
-  if (timeout < 0) {
+  if (timeout < 0)
     return RespondNow(Error(kErrorInvalidTimeout));
-  }
 
-  device_handle->IsochronousTransfer(
-      direction, generic_transfer.endpoint, buffer.get(), size, packets,
-      packet_length, timeout,
-      base::Bind(&UsbIsochronousTransferFunction::OnCompleted, this));
+  if (direction == device::USB_DIRECTION_INBOUND) {
+    device_handle->IsochronousTransferIn(
+        generic_transfer.endpoint, packet_lengths, timeout,
+        base::Bind(&UsbIsochronousTransferFunction::OnCompleted, this));
+  } else {
+    scoped_refptr<net::IOBuffer> buffer = CreateBufferForTransfer(
+        generic_transfer, direction, transfer.packets * transfer.packet_length);
+    if (!buffer.get())
+      return RespondNow(Error(kErrorMalformedParameters));
+
+    device_handle->IsochronousTransferOut(
+        generic_transfer.endpoint, buffer.get(), packet_lengths, timeout,
+        base::Bind(&UsbIsochronousTransferFunction::OnCompleted, this));
+  }
   return RespondLater();
 }
 
+void UsbIsochronousTransferFunction::OnCompleted(
+    scoped_refptr<net::IOBuffer> data,
+    const std::vector<UsbDeviceHandle::IsochronousPacket>& packets) {
+  size_t length = std::accumulate(
+      packets.begin(), packets.end(), 0,
+      [](const size_t& a, const UsbDeviceHandle::IsochronousPacket& packet) {
+        return a + packet.transferred_length;
+      });
+  scoped_ptr<char[]> buffer(new char[length]);
+
+  UsbTransferStatus status = device::USB_TRANSFER_COMPLETED;
+  size_t buffer_offset = 0;
+  size_t data_offset = 0;
+  for (const auto& packet : packets) {

[scheib, 2016/01/27 01:42:13]

test for an example of an error here.

[Reilly Grant (use Gerrit), 2016/01/29 23:25:36]

Done.

+    // Capture the error status of the first unsuccessful packet.
+    if (status == device::USB_TRANSFER_COMPLETED &&
+        packet.status != device::USB_TRANSFER_COMPLETED) {
+      status = packet.status;
+    }
+
+    memcpy(&buffer[buffer_offset], data->data() + data_offset,

[scheib, 2016/01/27 01:42:13]

Is there test coverage for this API bindings code?

[Reilly Grant (use Gerrit), 2016/01/29 23:25:36]

Yes, in //extensions/test/data/api_test/usb.

+           packet.transferred_length);
+    buffer_offset += packet.transferred_length;
+    data_offset += packet.length;
+  }
+
+  scoped_ptr<base::DictionaryValue> transfer_info(new base::DictionaryValue());
+  transfer_info->SetInteger(kResultCodeKey, status);
+  transfer_info->Set(kDataKey,
+                     new base::BinaryValue(std::move(buffer), length));
+  if (status == device::USB_TRANSFER_COMPLETED) {
+    Respond(OneArgument(std::move(transfer_info)));
+  } else {
+    scoped_ptr<base::ListValue> error_args(new base::ListValue());
+    error_args->Append(std::move(transfer_info));
+    // Returning arguments with an error is wrong but we're stuck with it.

[scheib, 2016/01/27 01:42:13]

'wrong'? why? deprecated? 

[Reilly Grant (use Gerrit), 2016/01/29 23:25:36]

It wasn't supposed to work but it does and some APIs now depend on it.
ExtensionFunctions are only supposed to either SetResult or SetError. If you do
both the callback is executed with the result and chrome.runtime.lastError is
set.

[scheib, 2016/01/30 22:01:06]

Please explain it in the code comment.

+    Respond(ErrorWithArguments(std::move(error_args),
+                               ConvertTransferStatusToApi(status)));
+  }
+}
+
 UsbResetDeviceFunction::UsbResetDeviceFunction() {
 }