CEC: Fix a regression bug

The HdmiControlService.getActiveSource() has a regression (exception)
when calling getDeviceInfoByPath since method should be called on
a service thread. Introduced a method that can be invoked safely
from the main thread.

Bug: 19170884
Change-Id: I393161e08c916270faf46147a97076bc573b808f

services/core/java/com/android/server/hdmi/HdmiCecLocalDeviceTv.java

@@ -1455,6 +1455,25 @@ final class HdmiCecLocalDeviceTv extends HdmiCecLocalDevice {
         return null;
     }
 
+    /**
+     * Returns the {@link HdmiDeviceInfo} instance whose physical address matches
+     * the given routing path. This is the version accessible safely from threads
+     * other than service thread.
+     *
+     * @param path routing path or physical address
+     * @return {@link HdmiDeviceInfo} if the matched info is found; otherwise null
+     */
+    HdmiDeviceInfo getSafeDeviceInfoByPath(int path) {
+        synchronized (mLock) {
+            for (HdmiDeviceInfo info : mSafeAllDeviceInfos) {
+                if (info.getPhysicalAddress() == path) {
+                    return info;
+                }
+            }
+            return null;
+        }
+    }
+
     /**
      * Whether a device of the specified physical address and logical address exists
      * in a device info list. However, both are minimal condition and it could

services/core/java/com/android/server/hdmi/HdmiControlService.java

@@ -1196,7 +1196,7 @@ public final class HdmiControlService extends SystemService {
             }
             int activePath = tv.getActivePath();
             if (activePath != HdmiDeviceInfo.PATH_INVALID) {
-                HdmiDeviceInfo info = tv.getDeviceInfoByPath(activePath);
+                HdmiDeviceInfo info = tv.getSafeDeviceInfoByPath(activePath);
                 return (info != null) ? info : new HdmiDeviceInfo(activePath, tv.getActivePortId());
             }
             return null;