MidiManagerAndroid: containers' clear and empty check were not matched

In Finalize(), MidiManagerAndroid clears |input_port_to_index_| and
|output_port_to_index_| explicitly, but checks |all_input_ports| and
|all_output_ports| to be empty in the destructor.

We should clear and check all four members in Finalize() and destructor.

Bug: 788684
Change-Id: Ia60f57a6faedb89559b0bb1019605bbcc0b78522
Reviewed-on: https://chromium-review.googlesource.com/790076
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519590}

media/midi/midi_manager_android.cc

@@ -55,7 +55,9 @@ MidiManagerAndroid::~MidiManagerAndroid() {
   base::AutoLock lock(lock_);
   DCHECK(devices_.empty());
   DCHECK(all_input_ports_.empty());
+  DCHECK(input_port_to_index_.empty());
   DCHECK(all_output_ports_.empty());
+  DCHECK(output_port_to_index_.empty());
   DCHECK(raw_manager_.is_null());
 }
 
@@ -79,7 +81,9 @@ void MidiManagerAndroid::Finalize() {
   // is enabled by default.
   base::AutoLock lock(lock_);
   devices_.clear();
+  all_input_ports_.clear();
   input_port_to_index_.clear();
+  all_output_ports_.clear();
   output_port_to_index_.clear();
   raw_manager_.Reset();
 }