Bug 875677 - Modify the logic of sending 'callheld' indicator to fit HFP 1.6, r=gyeh

According to HFP spec 1.6, we should update callheld status very carefully when
the status of other calls are changed.

dom/bluetooth/BluetoothHfpManager.cpp

@@ -1282,7 +1282,11 @@ BluetoothHfpManager::HandleCallStateChanged(uint32_t aCallIndex,
 
   switch (aCallState) {
     case nsITelephonyProvider::CALL_STATE_HELD:
-      sCINDItems[CINDType::CALLHELD].value = CallHeldState::ONHOLD_ACTIVE;
+      if (!FindFirstCall(nsITelephonyProvider::CALL_STATE_CONNECTED)) {
+        sCINDItems[CINDType::CALLHELD].value = CallHeldState::ONHOLD_NOACTIVE;
+      } else {
+        sCINDItems[CINDType::CALLHELD].value = CallHeldState::ONHOLD_ACTIVE;
+      }
       SendCommand("+CIEV: ", CINDType::CALLHELD);
       break;
     case nsITelephonyProvider::CALL_STATE_INCOMING:
@@ -1340,25 +1344,27 @@ BluetoothHfpManager::HandleCallStateChanged(uint32_t aCallIndex,
           UpdateCIND(CINDType::CALL, CallState::IN_PROGRESS, aSend);
           UpdateCIND(CINDType::CALLSETUP, CallSetupState::NO_CALLSETUP, aSend);
           break;
-        case nsITelephonyProvider::CALL_STATE_HELD:
-          // Besides checking if there is still held calls, another thing we
-          // need to consider is the state change when receiving AT+CHLD=2.
-          // Assume that there is one active call(c1) and one call on hold(c2).
-          // We got AT+CHLD=2, which swaps active/held position. The first
-          // action would be c2 -> ACTIVE, then c1 -> HELD. When we get the
-          // CallStateChanged event of c2 becoming ACTIVE, we enter here.
-          // However we can't send callheld=0 at this time because we should
-          // see c2 -> ACTIVE + c1 -> HELD as one operation. That's the reason
-          // why I added the GetNumberOfCalls() condition check.
-          if (!FindFirstCall(nsITelephonyProvider::CALL_STATE_HELD) &&
-              GetNumberOfCalls(
-                nsITelephonyProvider::CALL_STATE_CONNECTED) == 1) {
-            UpdateCIND(CINDType::CALLHELD, CallHeldState::NO_CALLHELD, aSend);
-          }
-          break;
         default:
           NS_WARNING("Not handling state changed");
       }
+
+      // = Handle callheld separately =
+      // Besides checking if there is still held calls, another thing we
+      // need to consider is the state change when receiving AT+CHLD=2.
+      // Assume that there is one active call(c1) and one call on hold(c2).
+      // We got AT+CHLD=2, which swaps active/held position. The first
+      // action would be c2 -> ACTIVE, then c1 -> HELD. When we get the
+      // CallStateChanged event of c2 becoming ACTIVE, we enter here.
+      // However we can't send callheld=0 at this time because we should
+      // see c2 -> ACTIVE + c1 -> HELD as one operation. That's the reason
+      // why I added the GetNumberOfCalls() condition check.
+      if (GetNumberOfCalls(nsITelephonyProvider::CALL_STATE_CONNECTED) == 1) {
+        if (FindFirstCall(nsITelephonyProvider::CALL_STATE_HELD)) {
+          UpdateCIND(CINDType::CALLHELD, CallHeldState::ONHOLD_ACTIVE, aSend);
+        } else if (prevCallState == nsITelephonyProvider::CALL_STATE_HELD) {
+          UpdateCIND(CINDType::CALLHELD, CallHeldState::NO_CALLHELD, aSend);
+        }
+      }
       break;
     case nsITelephonyProvider::CALL_STATE_DISCONNECTED:
       switch (prevCallState) {
@@ -1378,13 +1384,19 @@ BluetoothHfpManager::HandleCallStateChanged(uint32_t aCallIndex,
             UpdateCIND(CINDType::CALL, CallState::NO_CALL, aSend);
           }
           break;
-        case nsITelephonyProvider::CALL_STATE_HELD:
-          UpdateCIND(CINDType::CALLHELD, CallHeldState::NO_CALLHELD, aSend);
-          break;
         default:
           NS_WARNING("Not handling state changed");
       }
 
+      // Handle held calls separately
+      if (!FindFirstCall(nsITelephonyProvider::CALL_STATE_HELD)) {
+        UpdateCIND(CINDType::CALLHELD, CallHeldState::NO_CALLHELD, aSend);
+      } else if (!FindFirstCall(nsITelephonyProvider::CALL_STATE_CONNECTED)) {
+        UpdateCIND(CINDType::CALLHELD, CallHeldState::ONHOLD_NOACTIVE, aSend);
+      } else {
+        UpdateCIND(CINDType::CALLHELD, CallHeldState::ONHOLD_ACTIVE, aSend);
+      }
+
       // -1 is necessary because call 0 is an invalid (padding) call object.
       if (mCurrentCallArray.Length() - 1 ==
           GetNumberOfCalls(nsITelephonyProvider::CALL_STATE_DISCONNECTED)) {