Added trace query code and wired tracing through BrowserProxy so tests can run traces.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index eef54c324159487ffae38b7f395953bfe4d82798..985bf80f9754f958c01963ea77478162fcbaa0d2 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -6566,6 +6566,10 @@ error::Error GLES2DecoderImpl::HandleSwapBuffers(
     uint32 immediate_data_size, const gles2::SwapBuffers& c) {
   bool is_offscreen = !!offscreen_target_frame_buffer_.get();
   int this_frame_number = frame_number_++;
+  // This event is used by frame_rate_tests:
+  TRACE_EVENT_INSTANT1("test_frame_rate_tests", "SwapBuffers", "is_GPU",
+      gfx::GetGLImplementation() == gfx::kGLImplementationDesktopGL ||
+      gfx::GetGLImplementation() == gfx::kGLImplementationEGLGLES2);
   TRACE_EVENT2("gpu", "GLES2DecoderImpl::HandleSwapBuffers",
                "offscreen", is_offscreen,
                "frame", this_frame_number);