Bluetooth API: improve discovery

chrome/browser/extensions/api/bluetooth/bluetooth_api.cc

Index: chrome/browser/extensions/api/bluetooth/bluetooth_api.cc
diff --git a/chrome/browser/extensions/api/bluetooth/bluetooth_api.cc b/chrome/browser/extensions/api/bluetooth/bluetooth_api.cc
index 90528caa1701bac0f631a6ede8a33793493c129b..64dbfccf616462ef6a3a03c178e346cbfec4c4ca 100644
--- a/chrome/browser/extensions/api/bluetooth/bluetooth_api.cc
+++ b/chrome/browser/extensions/api/bluetooth/bluetooth_api.cc
@@ -48,12 +48,12 @@ const char kCouldNotGetLocalOutOfBandPairingData[] =
     "Could not get local Out Of Band Pairing Data";
 const char kCouldNotSetOutOfBandPairingData[] =
     "Could not set Out Of Band Pairing Data";
+const char kDiscoveryInProgress[] = "Discovery already in progress";
 const char kFailedToConnect[] = "Connection failed";
 const char kInvalidDevice[] = "Invalid device";
 const char kServiceDiscoveryFailed[] = "Service discovery failed";
 const char kSocketNotFoundError[] = "Socket not found: invalid socket id";
-const char kStartDiscoveryFailed[] =
-    "Starting discovery failed, or already discovering";
+const char kStartDiscoveryFailed[] = "Starting discovery failed";
 const char kStopDiscoveryFailed[] = "Failed to stop discovery";
 
 }  // namespace
@@ -456,11 +456,12 @@ void BluetoothStartDiscoveryFunction::OnErrorCallback() {
 bool BluetoothStartDiscoveryFunction::RunImpl() {
   GetEventRouter(profile())->SetSendDiscoveryEvents(true);
 
-  // BluetoothAdapter will throw an error if we SetDiscovering(true) when
-  // discovery is already in progress
+  // Fail if discovery is already in progress: this extension has missed all
+  // discovered devices so far.  It should re-try discovery after discovery has
+  // finished.

[asargent_no_longer_on_chrome, 2012/07/24 20:29:45]

Random thought- this can happen because *another* app has already started
discovery right? Would it make sense to queue up the request instead of making
the app call again on its own?

Alternatively, is it possible and would it make sense to cache the results of
the currently executing discovery, so we can deliver them to anyone who asks
while discovery is underway?

[bryeung, 2012/08/03 20:08:37]

I had originally decided against this, but your comment made me reconsider and I
think you're right: caching the devices and replaying them is what I would want
if I were a user of the API.  Fixed.

   if (GetMutableAdapter(profile())->IsDiscovering()) {
-    SendResponse(true);
-    return true;
+    SetError(kDiscoveryInProgress);
+    return false;
   }
 
   GetMutableAdapter(profile())->SetDiscovering(true,