Fix usb_host mojom connection error.

Fix usb_host mojom connection error when OpenDeivce is rejected.

When app call OpenDevice from Android side, it can be rejected because
1. app has not requested for permission.
2. permission_broker decides the node is in use.
In these cases we return mojo::ScopedHandle() from Chrome to Android.
And case cause mojom connection error.

connection error.

Test: return mojo::ScopedHandle() to OpenDeivce and no more mojom
Bug: 922675
Change-Id: I1de5eb17cca35d57f96afc7d10de6312659253b9
Reviewed-on: https://chromium-review.googlesource.com/c/1416132Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
Commit-Queue: Long Cheng <lgcheng@google.com>
Cr-Commit-Position: refs/heads/master@{#634766}

components/arc/common/usb_host.mojom

@@ -2,13 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Next MinVersion: 3
+// Next MinVersion: 4
 module arc.mojom;
 
 // re-use device.mojom.UsbDeviceInfo
 import "device/usb/public/mojom/device.mojom";
 
-// Next method ID: 3
+// Next method ID: 4
 interface UsbHostHost {
   // Tries to open the USB device node for the device named 'guid' for caller
   // 'pkg_name' and returns an open file descriptor to this node. 'pkg_name'
@@ -16,8 +16,20 @@ interface UsbHostHost {
   // call will fail. Note the 'pkg_name' is informational purposes only, there
   // is no effective way that host can restrict access to only a specific
   // package at the security boundary formed by this Mojo interface.
-  OpenDevice@0(string guid,
-               [MinVersion=1] string? pkg_name) => (handle usb_fd);
+  // Deprecated.
+  OpenDeviceDeprecated@0(string guid,
+                         [MinVersion=1] string? pkg_name) => (handle usb_fd);
+
+  // Tries to open the USB device node for the device named 'guid' for caller
+  // 'pkg_name' and returns an open file descriptor to this node. 'pkg_name'
+  // needs to have previously called RequestPermission for this 'guid' else this
+  // call will fail. Note the 'pkg_name' is informational purposes only, there
+  // is no effective way that host can restrict access to only a specific
+  // package at the security boundary formed by this Mojo interface.
+  // When app tries to open a device without requesting permission, or
+  // permission_broker rejects the open request, empty handle will be returned.
+  [MinVersion=3] OpenDevice@3(string guid, string? pkg_name) =>
+      (handle? usb_fd);
 
   // Returns the USB device descriptors for the device named 'guid'.
   GetDeviceInfo@1(string guid) => (string device_name,

components/arc/usb/usb_host_bridge.cc

@@ -166,6 +166,14 @@ void ArcUsbHostBridge::OpenDevice(const std::string& guid,
                    base::Bind(&OnDeviceOpenError, repeating_callback));
 }
 
+void ArcUsbHostBridge::OpenDeviceDeprecated(
+    const std::string& guid,
+    const base::Optional<std::string>& package,
+    OpenDeviceCallback callback) {
+  LOG(ERROR) << "ArcUsbHostBridge::OpenDeviceDeprecated is deprecated";
+  OpenDevice(guid, package, std::move(callback));
+}
+
 void ArcUsbHostBridge::GetDeviceInfo(const std::string& guid,
                                      GetDeviceInfoCallback callback) {
   if (!usb_service_) {

components/arc/usb/usb_host_bridge.h

@@ -53,6 +53,9 @@ class ArcUsbHostBridge : public KeyedService,
                          const std::string& package,
                          bool interactive,
                          RequestPermissionCallback callback) override;
+  void OpenDeviceDeprecated(const std::string& guid,
+                            const base::Optional<std::string>& package,
+                            OpenDeviceCallback callback) override;
   void OpenDevice(const std::string& guid,
                   const base::Optional<std::string>& package,
                   OpenDeviceCallback callback) override;