Part of fix for double spins & faster startup

This change alters the way that the media player
interacts with the Widevine adaptive streaming buffer
logic.  It eliminates the reliance on cached buffer
duration to determine pause/play states and instead
only generates buffering events when the widevine
library is not producing data (i.e. when it is
buffering).  This eliminates unnecessary pause and
rebuffer cycles, reducing startup time and the
frequency and duration of spinners.

Multi-repo commit, depends on related changes in frameworks/av

Change-Id: I5b71f954268fbd390eed7f27db98a1bb470d5cfb
related-to-bug:6503294
related-to-bug:6463780

proprietary/wvm/WVMMediaSource.cpp

@@ -35,6 +35,7 @@ WVMMediaSource::WVMMediaSource(WVSession *session, WVEsSelector esSelector,
       mIsLiveStream(isLive),
       mNewSegment(false),
       mCryptoInitialized(false),
+      mIsStalled(false),
       mGroup(NULL),
       mKeyTime(0),
       mDts(0),
@@ -203,6 +204,8 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
 {
     Mutex::Autolock autoLock(mLock);
 
+    mIsStalled = false;
+
     CHECK(mStarted);
 
     *buffer = NULL;
@@ -333,16 +336,20 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
                 return ERROR_IO;
             } else {
                 // Didn't get anything, sleep a bit so we don't hog the CPU then try again
+                if (retryCount > 10)
+                    mIsStalled = true;
                 usleep(10000);
                 continue;
             }
         }
 
+
 #define PCR_HZ 90000
         mKeyTime = (int64_t)mPts * 1000000 / PCR_HZ;
 
         if (seekNextSync && ((mKeyTime < seekTimeUs) || !syncFrame)) {
             // drop frames up to next sync if requested
+            mIsStalled = true;
             usleep(10000);
 #ifdef REQUIRE_SECURE_BUFFERS
             mDecryptContext.Initialize(mediaBuf);
@@ -351,6 +358,8 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
             continue;
         }
 
+        mIsStalled = false;
+
         if (offset + bytesRead < mediaBuf->size())
             break;