BufferQueue improvements and APIs changes

this is the first step of a series of improvements to
BufferQueue. A few things happen in this change:

- setSynchronousMode() goes away as well as the SynchronousModeAllowed flag
- BufferQueue now defaults to (what used to be) synchronous mode
- a new "controlled by app" flag is passed when creating consumers and producers
  those flags are used to put the BufferQueue in a mode where it
  will never block if both flags are set. This is achieved by:
  - returning an error from dequeueBuffer() if it would block
  - making sure a buffer is always available by replacing
    the previous buffer with the new one in queueBuffer()
    (note: this is similar to what asynchrnous mode used to be)

Note: in this change EGL's swap-interval 0 is broken; this will be
fixed in another change.

Change-Id: I691f9507d6e2e158287e3039f2a79a4d4434211d
diff --git a/libs/gui/CpuConsumer.cpp b/libs/gui/CpuConsumer.cpp
index adddfc2..b8c00af 100644
--- a/libs/gui/CpuConsumer.cpp
+++ b/libs/gui/CpuConsumer.cpp
@@ -31,15 +31,14 @@
 namespace android {
 
 CpuConsumer::CpuConsumer(const sp<BufferQueue>& bq,
-        uint32_t maxLockedBuffers, bool synchronousMode) :
-    ConsumerBase(bq),
+        uint32_t maxLockedBuffers, bool controlledByApp) :
+    ConsumerBase(bq, controlledByApp),
     mMaxLockedBuffers(maxLockedBuffers),
     mCurrentLockedBuffers(0)
 {
     // Create tracking entries for locked buffers
     mAcquiredBuffers.insertAt(0, maxLockedBuffers);
 
-    mBufferQueue->setSynchronousMode(synchronousMode);
     mBufferQueue->setConsumerUsageBits(GRALLOC_USAGE_SW_READ_OFTEN);
     mBufferQueue->setMaxAcquiredBufferCount(maxLockedBuffers);
 }