Fix latency tests

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 2060 matching lines @@
       // milliseconds sometimes (!) so this is skipped completely for drawRects
       // that are triggered by BuffersSwapped messages.
       [[NSColor clearColor] set];
       NSRectFill(dirtyRect);
     }
 
     // TODO(thakis): Register for backing scale factor change events and pass
     // that on.
     renderWidgetHostView_->compositing_iosurface_->DrawIOSurface(
         self, ScaleFactor(self));
+    // For latency_tests.cc:
+    UNSHIPPED_TRACE_EVENT_INSTANT0("test_gpu", "CompositorSwapBuffersComplete");
     renderWidgetHostView_->AckPendingSwapBuffers();
     return;
   }
 
   if (backingStore) {
     // Note: All coordinates are in view units, not pixels.
     gfx::Rect bitmapRect(0, 0,
                          backingStore->size().width(),
                          backingStore->size().height());
 
@@ skipping 998 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end