Add infrastructure for a USB device blocklist.

chrome/browser/usb/usb_blocklist.cc

Index: chrome/browser/usb/usb_blocklist.cc
diff --git a/chrome/browser/usb/usb_blocklist.cc b/chrome/browser/usb/usb_blocklist.cc
new file mode 100644
index 0000000000000000000000000000000000000000..11241cb650ddd28b05db1624db66425d0051481d
--- /dev/null
+++ b/chrome/browser/usb/usb_blocklist.cc
@@ -0,0 +1,107 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/usb/usb_blocklist.h"
+
+#include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "components/variations/variations_associated_data.h"
+#include "device/usb/usb_device.h"
+
+namespace {
+
+static base::LazyInstance<UsbBlocklist>::Leaky g_singleton =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+// The == and < operators are necessary to use Entries in std::set.
+bool operator==(const UsbBlocklist::Entry& a, const UsbBlocklist::Entry& b) {
+  return a.vendor_id == b.vendor_id && a.product_id == b.product_id &&
+         a.version == b.version;
+}
+
+bool operator<(const UsbBlocklist::Entry& a, const UsbBlocklist::Entry& b) {
+  if (a.vendor_id == b.vendor_id) {
+    if (a.product_id == b.product_id)
+      return a.version < b.version;
+    return a.product_id < b.product_id;
+  }
+  return a.vendor_id < b.vendor_id;
+}
+
+UsbBlocklist::Entry::Entry(uint16_t vendor_id,
+                           uint16_t product_id,
+                           uint16_t version)
+    : vendor_id(vendor_id), product_id(product_id), version(version) {}
+
+UsbBlocklist::~UsbBlocklist() {}
+
+// static
+UsbBlocklist& UsbBlocklist::Get() {
+  return g_singleton.Get();
+}
+
+void UsbBlocklist::Exclude(const Entry& entry) {
+  blocklisted_devices_.insert(entry);
+}
+
+void UsbBlocklist::Exclude(base::StringPiece blocklist_string) {
+  for (const auto& entry :
+       base::SplitStringPiece(blocklist_string, ",", base::TRIM_WHITESPACE,
+                              base::SPLIT_WANT_NONEMPTY)) {
+    std::vector<base::StringPiece> components = base::SplitStringPiece(
+        entry, ":", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+    if (components.size() != 3 || components[0].size() != 4 ||
+        components[1].size() != 4 || components[2].size() != 4) {
+      continue;
+    }
+
+    uint32_t vendor_id;
+    uint32_t product_id;
+    uint32_t version;
+    if (!base::HexStringToUInt(components[0], &vendor_id) ||
+        !base::HexStringToUInt(components[1], &product_id) ||
+        !base::HexStringToUInt(components[2], &version)) {
+      continue;
+    }
+
+    Exclude(Entry(vendor_id, product_id, version));
+  }
+}
+
+bool UsbBlocklist::IsExcluded(const Entry& entry) {
+  return base::ContainsValue(blocklisted_devices_, entry);
+}
+
+bool UsbBlocklist::IsExcluded(scoped_refptr<const device::UsbDevice> device) {
+  return IsExcluded(Entry(device->vendor_id(), device->product_id(),
+                          device->device_version()));
+}
+
+void UsbBlocklist::ResetToDefaultValuesForTest() {
+  blocklisted_devices_.clear();
+  PopulateWithDefaultValues();
+  PopulateWithServerProvidedValues();
+}
+
+UsbBlocklist::UsbBlocklist() {
+  PopulateWithDefaultValues();
+  PopulateWithServerProvidedValues();
+}
+
+void UsbBlocklist::PopulateWithDefaultValues() {
+  // To add a device to the blocklist add an entry here as well as configuring
+  // a Finch trial so that the blocklist update is pushed out to existing users
+  // as quickly as possible, e.g.:
+  //
+  // Exclude({ 0x18D0, 0x58F0, 0x1BAD });
+}
+
+void UsbBlocklist::PopulateWithServerProvidedValues() {
+  std::string blocklist_string = variations::GetVariationParamValue(
+      "WebUSBBlocklist", "blocklist_additions");
+  Exclude(blocklist_string);
+}