Add ConsumerBase::isAbandoned

Bug: 20105644
Change-Id: I21526b5397ea51a15500c44a99daa9d75fc4ea67
(cherry picked from commit e478305181)

include/gui/ConsumerBase.h

@@ -56,6 +56,9 @@ public:
     // or by OpenGL ES as a texture) then those buffer will remain allocated.
     void abandon();
 
+    // Returns true if the ConsumerBase is in the 'abandoned' state
+    bool isAbandoned();
+
     // set the name of the ConsumerBase that will be used to identify it in
     // log messages.
     void setName(const String8& name);

libs/gui/ConsumerBase.cpp

@@ -171,6 +171,11 @@ void ConsumerBase::abandonLocked() {
     mConsumer.clear();
 }
 
+bool ConsumerBase::isAbandoned() {
+    Mutex::Autolock _l(mMutex);
+    return mAbandoned;
+}
+
 void ConsumerBase::setFrameAvailableListener(
         const wp<FrameAvailableListener>& listener) {
     CB_LOGV("setFrameAvailableListener");