wifi(interface): Add Iface objects

Create a child object under IWifiChip to represent each interface
within the chip. Each iface object has a |type| & |ifname| which should
help us uniquely identify them. This should help us expose methods that
are applicable only to a specific interface type.

While there,
Assign a unique id to every chip on the device.
Add IWifi.listChipIds() to retrieve the list of chip Id's avaiable on the
device. IWifi.getChip() will now use the provided Id to retrieve the
corresponding IWifiChip object(because HIDL language doesn't support
vec<HIDL objects>).

Bug: 31943042
Bug: 32003988
Test: Interface compiles (not implementation)
Change-Id: I723007566ca4220362c02d0f452753fee4e31fce
diff --git a/wifi/1.0/IWifi.hal b/wifi/1.0/IWifi.hal
index d1311f5..9e09348 100644
--- a/wifi/1.0/IWifi.hal
+++ b/wifi/1.0/IWifi.hal
@@ -70,10 +70,22 @@
   @callflow(next={"registerEventCallback", "start", "stop"})
   oneway stop();
 
-  // TODO(b/30570663) return vec<IWifiChip> instead
   /**
-   * Get the configurable chip on the device.
+   * Retrieve the list of all chip Id's on the device.
+   * The corresponding |IWifiChip| object for any chip can be
+   * retrieved using |getChip| method.
+   *
+   * @return chipIds List of all chip Id's on the device.
    */
   @callflow(next={"*"})
-  getChip() generates (IWifiChip chip);
+  getChipIds() generates (vec<ChipId> chipIds);
+
+  /**
+   * Gets a HIDL interface object for the chip corresponding to the
+   * provided chipId.
+   *
+   * @return chip HIDL interface object representing the chip.
+   */
+  @callflow(next={"*"})
+  getChip(ChipId chipId) generates (IWifiChip chip);
 };