ppapi: add helper methods to MediaStreamBufferManager

ppapi/shared_impl/media_stream_buffer_manager_unittest.cc

Index: ppapi/shared_impl/media_stream_buffer_manager_unittest.cc
diff --git a/ppapi/shared_impl/media_stream_buffer_manager_unittest.cc b/ppapi/shared_impl/media_stream_buffer_manager_unittest.cc
index 090cb2a36d6718874493c6e5b5c9efbb6f53be65..2ea61f864bc79dba9e5eeb839037b6ee0abb9db4 100644
--- a/ppapi/shared_impl/media_stream_buffer_manager_unittest.cc
+++ b/ppapi/shared_impl/media_stream_buffer_manager_unittest.cc
@@ -51,25 +51,30 @@ TEST(MediaStreamBufferManager, General) {
                                    shared_memory.Pass(),
                                    true));
 
+
     int8_t* memory = reinterpret_cast<int8_t*>(manager.GetBufferPointer(0));
     EXPECT_NE(static_cast<int8_t*>(NULL), memory);
 
     EXPECT_EQ(kNumberOfBuffers, manager.number_of_buffers());
     EXPECT_EQ(kBufferSize, manager.buffer_size());
+    EXPECT_EQ(kNumberOfBuffers, manager.BuffersAvailable());
 
     // Test DequeueBuffer() and GetBufferPointer()
     for (int32_t i = 0; i < kNumberOfBuffers; ++i) {
+      EXPECT_EQ(kNumberOfBuffers - i, manager.BuffersAvailable());
       EXPECT_EQ(i, manager.DequeueBuffer());
       EXPECT_EQ(reinterpret_cast<MediaStreamBuffer*>(memory + i * kBufferSize),
                 manager.GetBufferPointer(i));
     }
 
+    EXPECT_EQ(0, manager.BuffersAvailable());
     manager.EnqueueBuffer(0);
     manager.EnqueueBuffer(4);
     manager.EnqueueBuffer(3);
     manager.EnqueueBuffer(1);
     manager.EnqueueBuffer(2);
     EXPECT_EQ(5, delegate.new_buffer_enqueue_counter_);
+    EXPECT_EQ(kNumberOfBuffers, manager.BuffersAvailable());
 
     EXPECT_EQ(0, manager.DequeueBuffer());
     EXPECT_EQ(4, manager.DequeueBuffer());
@@ -108,6 +113,7 @@ TEST(MediaStreamBufferManager, General) {
 
     EXPECT_EQ(kNumberOfBuffers, manager.number_of_buffers());
     EXPECT_EQ(kBufferSize, manager.buffer_size());
+    EXPECT_EQ(0, manager.BuffersAvailable());
 
     // Test DequeueBuffer() and GetBufferPointer()
     for (int32_t i = 0; i < kNumberOfBuffers; ++i) {