Turn off computation of the interest rect in cc in synchronized paint mode.

content/browser/gpu/compositor_util.cc

Index: content/browser/gpu/compositor_util.cc
diff --git a/content/browser/gpu/compositor_util.cc b/content/browser/gpu/compositor_util.cc
index 895044d71eaeacd311ec9c131eb9a8d37162694c..e4e8fd6130260dc485b0006c0cf22f1884c1909a 100644
--- a/content/browser/gpu/compositor_util.cc
+++ b/content/browser/gpu/compositor_util.cc
@@ -165,6 +165,12 @@ bool IsPropertyTreeVerificationEnabled() {
   return command_line.HasSwitch(cc::switches::kEnablePropertyTreeVerification);
 }
 
+bool IsBlinkSynchronizedPaintingEnabled() {
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+  return command_line.HasSwitch(switches::kEnableBlinkSynchronizedPainting);
+}
+
 int NumberOfRendererRasterThreads() {
   int num_processors = base::SysInfo::NumberOfProcessors();