gpu: Use explicit atomics instead of assuming that 32bit read/writes are atomic.

gpu/command_buffer/client/query_tracker.h

Index: gpu/command_buffer/client/query_tracker.h
diff --git a/gpu/command_buffer/client/query_tracker.h b/gpu/command_buffer/client/query_tracker.h
index 9e7f501768b74a5bbfa4dccfb2bee6e153622dfa..ce9cc6b9479d6e96cf590e375d775d370edf1803 100644
--- a/gpu/command_buffer/client/query_tracker.h
+++ b/gpu/command_buffer/client/query_tracker.h
@@ -105,6 +105,8 @@ class GLES2_IMPL_EXPORT QueryTracker {
     void MarkAsActive() {
       state_ = kActive;
       ++submit_count_;
+      if (submit_count_ == INT_MAX)
+        submit_count_ = 1;
     }
 
     void MarkAsPending(int32 token) {
@@ -113,7 +115,7 @@ class GLES2_IMPL_EXPORT QueryTracker {
       flushed_ = false;
     }
 
-    uint32 submit_count() const {
+    int32 submit_count() const {
       return submit_count_;
     }
 
@@ -144,7 +146,7 @@ class GLES2_IMPL_EXPORT QueryTracker {
     GLenum target_;
     QuerySyncManager::QueryInfo info_;
     State state_;
-    uint32 submit_count_;
+    int32 submit_count_;
     int32 token_;
     bool flushed_;
     uint64 client_begin_time_us_; // Only used for latency query target.