Remove flushAndSubit from SkiaPipeline renderFrame.

Previously we would submit a command buffer for the
frames draws and then immediately submit a second
command buffer that had no commands and just an attached
semaphore. This merges those two submit calls into Skia
into one call.

Test: manual running of system of benches
Bug: 175913056

Change-Id: If0d054960de8b459814cbfa9289756f8ee9d4a93
(cherry picked from commit f16ba6019400ec7eb6ac7a2adc05ec06ad5661a1)
diff --git a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp
index 389fe7e..50eea31 100644
--- a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp
+++ b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp
@@ -105,7 +105,6 @@
     LightingInfo::updateLighting(lightGeometry, lightInfo);
     renderFrame(*layerUpdateQueue, dirty, renderNodes, opaque, contentDrawBounds, surface,
                 SkMatrix::I());
-    layerUpdateQueue->clear();
 
     // Draw visual debugging features
     if (CC_UNLIKELY(Properties::showDirtyRegions ||
@@ -113,9 +112,14 @@
         SkCanvas* profileCanvas = surface->getCanvas();
         SkiaProfileRenderer profileRenderer(profileCanvas);
         profiler->draw(profileRenderer);
-        profileCanvas->flush();
     }
 
+    {
+        ATRACE_NAME("flush commands");
+        surface->flushAndSubmit();
+    }
+    layerUpdateQueue->clear();
+
     // Log memory statistics
     if (CC_UNLIKELY(Properties::debugLevel != kDebugDisabled)) {
         dumpResourceCacheUsage();