Flush the pipe in skiaserve when we switch to GPU

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1789723003

Review URL: https://codereview.chromium.org/1789723003

1 files changed, 7 insertions, 0 deletions

diff --git a/tools/skiaserve/Request.cpp b/tools/skiaserve/Request.cpp
index f9ad867028..e0aad15aad 100644
--- a/tools/skiaserve/Request.cpp
+++ b/tools/skiaserve/Request.cpp
@@ -197,6 +197,13 @@ bool Request::enableGPU(bool enable) {
         if (surface) {
             fSurface.reset(surface);
             fGPUEnabled = true;
+
+            // When we switch to GPU, there seems to be some mystery draws in the canvas.  So we
+            // draw once to flush the pipe
+            // TODO understand what is actually happening here
+            fDebugCanvas->drawTo(this->getCanvas(), this->getLastOp());
+            this->getCanvas()->flush();
+
             return true;
         }
         return false;