Input latency performance test that uses tracing.

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 b110751bbc48b357a8c0849d9c0f3f37c4fd5fd2..42ba4969c1931df08d81f61a1aab05ba7628e8f0 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -3829,6 +3829,8 @@ error::Error GLES2DecoderImpl::HandleRegisterSharedIdsCHROMIUM(
 
 void GLES2DecoderImpl::DoClear(GLbitfield mask) {
   if (CheckBoundFramebuffersValid("glClear")) {
+    UNSHIPPED_TRACE_EVENT_INSTANT2("test_gpu", "DoClear", "red", clear_red_,
+                                   "green", clear_green_);
     ApplyDirtyState();
     glClear(mask);
   }
@@ -4137,6 +4139,7 @@ void GLES2DecoderImpl::DoBlitFramebufferEXT(
     glBlitFramebufferEXT(
         srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1, mask, filter);
   }
+  UNSHIPPED_TRACE_EVENT_INSTANT1("test_gpu", "DoBlit", "width", srcX1 - srcX0);

[nduca, 2011/12/21 20:24:23]

Is the idea to use this to connect a main-thread frame to a compositor-thread
frame? I have to say, i still can't quite grok the role of blit in our latency
detection flow...

[jbates, 2011/12/22 02:41:17]

Yes, exactly as you guessed. The blit represents the compositor consuming a
WebGL frame. This is done when the webgl context has MSAA -- I added a comment
to the html where it creates the context with antialias.

 }
 
 void GLES2DecoderImpl::DoRenderbufferStorageMultisample(
@@ -7228,8 +7231,10 @@ error::Error GLES2DecoderImpl::HandleSwapBuffers(
   bool is_offscreen = !!offscreen_target_frame_buffer_.get();
   int this_frame_number = frame_number_++;
   // TRACE_EVENT for gpu tests:
-  TRACE_EVENT_INSTANT1("test_gpu", "SwapBuffers",
-                       "GLImpl", static_cast<int>(gfx::GetGLImplementation()));
+  TRACE_EVENT_INSTANT2("test_gpu", "SwapBuffers",
+                       "GLImpl", static_cast<int>(gfx::GetGLImplementation()),
+                       "width", (is_offscreen ? offscreen_size_.width() :
+                                 surface_->GetSize().width()));
   TRACE_EVENT2("gpu", "GLES2DecoderImpl::HandleSwapBuffers",
                "offscreen", is_offscreen,
                "frame", this_frame_number);