Added thread annotations to FifoBuffer.

This CL adds thread annotations to FifoBuffer and adds a missing CritScope
for attribute access that is modified in locked code paths.

Review URL: https://codereview.webrtc.org/1677333002

Cr-Commit-Position: refs/heads/master@{#11535}

webrtc/base/stream.cc

@@ -741,6 +741,7 @@ StreamResult FifoBuffer::WriteOffset(const void* buffer, size_t bytes,
 }
 
 StreamState FifoBuffer::GetState() const {
+  CritScope cs(&crit_);
   return state_;
 }
 

webrtc/base/stream.h

@@ -542,20 +542,29 @@ class FifoBuffer : public StreamInterface {
   // Helper method that implements ReadOffset. Caller must acquire a lock
   // when calling this method.
   StreamResult ReadOffsetLocked(void* buffer, size_t bytes, size_t offset,
-                                size_t* bytes_read);
+                                size_t* bytes_read)
+      EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   // Helper method that implements WriteOffset. Caller must acquire a lock
   // when calling this method.
   StreamResult WriteOffsetLocked(const void* buffer, size_t bytes,
-                                 size_t offset, size_t* bytes_written);
+                                 size_t offset, size_t* bytes_written)
+      EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
-  StreamState state_;  // keeps the opened/closed state of the stream
-  scoped_ptr<char[]> buffer_;  // the allocated buffer
-  size_t buffer_length_;  // size of the allocated buffer
-  size_t data_length_;  // amount of readable data in the buffer
-  size_t read_position_;  // offset to the readable data
-  Thread* owner_;  // stream callbacks are dispatched on this thread
-  CriticalSection crit_;  // object lock
+  // keeps the opened/closed state of the stream
+  StreamState state_ GUARDED_BY(crit_);
+  // the allocated buffer
+  scoped_ptr<char[]> buffer_ GUARDED_BY(crit_);
+  // size of the allocated buffer
+  size_t buffer_length_ GUARDED_BY(crit_);
+  // amount of readable data in the buffer
+  size_t data_length_ GUARDED_BY(crit_);
+  // offset to the readable data
+  size_t read_position_ GUARDED_BY(crit_);
+  // stream callbacks are dispatched on this thread
+  Thread* owner_;
+  // object lock
+  CriticalSection crit_;
   RTC_DISALLOW_COPY_AND_ASSIGN(FifoBuffer);
 };