Added support for TimeStamp queries using QueryCounterEXT.

gpu/command_buffer/client/query_tracker.cc

Index: gpu/command_buffer/client/query_tracker.cc
diff --git a/gpu/command_buffer/client/query_tracker.cc b/gpu/command_buffer/client/query_tracker.cc
index 37a147878a7561cdb609ea536f4f275482c74955..c4ef5888fa617e7f618b02e7584938f4f50bcd3f 100644
--- a/gpu/command_buffer/client/query_tracker.cc
+++ b/gpu/command_buffer/client/query_tracker.cc
@@ -166,6 +166,14 @@ void QueryTracker::Query::End(GLES2Implementation* gl) {
   MarkAsPending(gl->helper()->InsertToken());
 }
 
+void QueryTracker::Query::QueryCounter(GLES2Implementation* gl) {
+  MarkAsActive();
+  flush_count_ = gl->helper()->flush_generation();
+  gl->helper()->QueryCounterEXT(target(), id(), shm_id(), shm_offset(),
+                                submit_count());
+  MarkAsPending(gl->helper()->InsertToken());
+}
+
 bool QueryTracker::Query::CheckResultsAvailable(
     CommandBufferHelper* helper) {
   if (Pending()) {
@@ -324,5 +332,31 @@ bool QueryTracker::EndQuery(GLenum target, GLES2Implementation* gl) {
   return true;
 }
 
+bool QueryTracker::QueryCounter(GLuint id, GLenum target,
+                                GLES2Implementation* gl) {
+  QueryTracker::Query* query = GetQuery(id);
+  if (!query) {
+    query = CreateQuery(id, target);
+    if (!query) {
+      gl->SetGLError(GL_OUT_OF_MEMORY,
+                     "glQueryCounterEXT",
+                     "transfer buffer allocation failed");
+      return false;
+    }
+  } else if (query->target() != target) {
+    gl->SetGLError(GL_INVALID_OPERATION,
+                   "glQueryCounterEXT",
+                   "target does not match");
+    return false;
+  }
+
+  // Spec is not clear how long an "active query" for a QueryCounter is since
+  // there is no ending mark such as glEndQuery. Just use the latest query
+  // until it has been deleted.
+  query->QueryCounter(gl);
+  current_queries_[query->target()] = query;

[piman, 2015/07/16 01:05:52]

According to my reading of the spec, the query never becomes current.

[David Yen, 2015/07/16 20:21:12]

Hmm, I will remove it then. Done.

+  return true;
+}
+
 }  // namespace gles2
 }  // namespace gpu