Remove deprecated FormattingFinished signal.

The FormattingFinished signal has long been removed from cros-disks
(CL:12022). Chrome has recently been updated to deprecate the use of
FormattingFinished signal as well (crrev.com/268398).

BUG=chromium:369877
TEST=Tested the following:
1. Insert a USB drive and format the mounted partition via Files.app.
   Verify that Files.app notifies the successful completion of the
   format operation.
2. Insert a write-protected SD card and format the mounted partition via
   Files.app. Verify that Files.app reports an error.
3. Verify that cros-disks only emits FormatCompleted signal, but not
   FormattingFinished signal, in both (1) and (2).

Change-Id: I34254e5a0a3cf7eeec8f8fdebabc43e3175502fd
Reviewed-on: https://chromium-review.googlesource.com/198313
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
diff --git a/cros_disks_server.cc b/cros_disks_server.cc
index 2a9e7d2..1a25611 100644
--- a/cros_disks_server.cc
+++ b/cros_disks_server.cc
@@ -182,14 +182,6 @@
 
 void CrosDisksServer::OnFormatCompleted(const string& device_path,
                                         FormatErrorType error_type) {
-  // TODO(benchan): Deprecate the FormattingFinished signal once Chrome
-  // switches to observe the FormatCompleted signal instead.
-  if (error_type != FORMAT_ERROR_NONE) {
-    FormattingFinished("!" + device_path);
-    LOG(ERROR) << "Failed to format '" << device_path << "'";
-  } else {
-    FormattingFinished(device_path);
-  }
   FormatCompleted(error_type, device_path);
 }
 
diff --git a/dbus_bindings/org.chromium.CrosDisks.xml b/dbus_bindings/org.chromium.CrosDisks.xml
index acb3e16..53197fa 100644
--- a/dbus_bindings/org.chromium.CrosDisks.xml
+++ b/dbus_bindings/org.chromium.CrosDisks.xml
@@ -137,9 +137,5 @@
       <arg name="device" type="s" direction="out">
       </arg>
     </signal>
-    <signal name="FormattingFinished">
-      <arg name="device" type="s" direction="out">
-      </arg>
-    </signal>
   </interface>
 </node>